
# Eat That Frog! — Brian Tracy

The title comes from Mark Twain: if you eat a live frog first thing in the morning, nothing worse can happen to you the rest of the day. Your frog is your most important, hardest task — the one you most want to avoid, and also the one that will have the greatest positive impact on your results. Do it first. Everything after that is easier.

This is the companion book to [Goals!](/blog/goals-by-brian-tracy) Where [Goals!](/blog/goals-by-brian-tracy) gives you the system for knowing where you are going, Eat That Frog gives you the daily discipline for actually getting there. The two books work as a pair.



## The Core Idea

You will never get everything done. There is always more to do than time to do it, and there always will be. The answer is not a better productivity app or a longer working day. The answer is to stop trying to do everything and instead identify the one task with the greatest consequences — your frog — and do that first, every single day, until it is completely finished.

"Everyone procrastinates. The difference between high performers and low performers is largely determined by what they choose to procrastinate on."

The three qualities that make this possible are decision, discipline, and determination. First, make a firm decision to build the habit of completing your most important task before anything else. Second, discipline yourself to practice the techniques below until they become automatic. Third, back everything with determination until the habits are permanently part of who you are.



## The 21 Techniques

### 1. Set the Table

Before anything else, get clear on what you want. Write it down — thinking on paper is essential. Set a deadline. List every action required to achieve it. Organise that list by priority and sequence. Then start immediately.

An average plan acted on vigorously beats a brilliant plan that sits on paper.

"Goals are the fuel in the furnace of achievement. The bigger your goals and the clearer they are, the more excited you become about achieving them."

### 2. Plan Every Day in Advance

Every minute spent planning saves ten minutes in execution. The first ten percent of time you spend planning saves ninety percent of the time required to carry the work out.

Use four lists running at all times:

- A master list of everything you need to do
- A monthly list for the coming month
- A weekly list updated at the end of each week
- A daily list written the evening before

Work from your daily list from the moment you begin. Never start the day without a written plan.

### 3. Apply the 80/20 Rule to Everything

Twenty percent of your tasks produce eighty percent of your results. Before you begin work each morning, ask: is this task in my top twenty percent or bottom eighty? Work only on the top twenty percent until it is done.

Resist the temptation to clear small tasks first just because they feel easy. Small tasks done efficiently are still small tasks. The payoff from completing a major task is always disproportionately greater than the effort required.

"One of the very worst uses of time is to do something very well that need not be done at all."

### 4. Consider the Consequences

Before starting any task, ask: what are the potential consequences of doing this, or not doing this? Long-term thinkers make far better daily decisions than short-term thinkers. The tasks with the biggest long-term consequences are always your real priorities, even when they feel uncomfortable to begin.

"Long-term thinking improves short-term decision making."

Successful people are those willing to delay gratification and make sacrifices now in exchange for far greater rewards later.

### 5. Practice Creative Procrastination

You cannot do everything. Since you must procrastinate on something, procrastinate deliberately on low-value tasks rather than high-value ones. Regularly ask: what can I stop doing right now that is not essential? What can I delegate? What can I eliminate entirely?

Saying no to the unimportant is what creates space for the important. High performers guard their time fiercely. They are as disciplined about what they choose not to do as about what they choose to do.

### 6. Use the ABCDE Method Every Day

Before you begin work, label every task on your list:

- A — must do, serious consequences if not done. Your frog.
- B — should do, mild consequences. Never do a B while an A remains.
- C — nice to do, no real consequences either way.
- D — delegate to someone else immediately.
- E — eliminate entirely. Ask honestly whether it needs doing at all.

Work through A tasks in order of priority — A1, A2, A3 — before touching anything else on the list. This single discipline, applied consistently, will transform your output.

### 7. Focus on Key Result Areas

Every role has five to seven key result areas — the specific outputs that define whether you are doing your job excellently. Write yours down. Grade yourself honestly from one to ten on each.

Your weakest key result area sets the ceiling for everything else. A chain breaks at its weakest link. Identify your weakest area and commit to improving it. Ask yourself: what one skill, if I developed it to excellence, would have the greatest positive impact on my career?

"Continuous learning is the minimum requirement for success in any field."

### 8. The Law of Three

Identify the three tasks that contribute the most value to your work. These three tasks typically account for ninety percent of the value you produce. Everything else is secondary. Do this exercise for your career, your finances, your relationships, and your health. Know your three most important frogs before you begin each day.

### 9. Prepare Thoroughly Before You Begin

Get everything you need ready before you start. Clear your desk of everything except what is relevant to the task in front of you. A clean, organised workspace produces a calmer, more focused mind.

Tracy's personal rule: get it eighty percent right and correct it later. Do not wait for perfect conditions. They never arrive. Start with what you have.

"An average plan vigorously executed is far better than a brilliant plan on which nothing is done."

### 10. Take It One Oil Barrel at a Time

When a task feels overwhelming, stop looking at the whole of it. Focus on the single next action. Start there. How do you eat an elephant? One bite at a time.

Once you begin, momentum builds naturally. The hardest part of any task is always getting started. The moment you put pen to paper, open the document, or make the first call, resistance drops and progress becomes possible.

"The hardest part of any important task is getting started. Once you actually begin work on a valuable task, you seem to be naturally motivated to continue."

### 11. Upgrade Your Key Skills Constantly

The more skilled you become at your most important tasks, the less you avoid them and the more naturally you move toward them. Read in your field for at least one hour every day. Attend courses and seminars. Listen to educational audio when travelling. The better you become at eating a particular type of frog, the more likely you are to simply plunge in and get it done.

"Anytime you stop striving to get better, you are bound to get worse."

### 12. Leverage Your Special Talents

Identify the things you do better than most people, the things that come naturally and produce your best results. Build your most important work around those strengths wherever possible. Delegate tasks that fall outside them. You perform at your best when working in your areas of natural excellence.

### 13. Identify Your Key Constraints

Something is always setting the speed at which you achieve your results. Ask honestly: what is the bottleneck? What is slowing me down most? In most cases the constraint is internal — a skill gap, a habit, a fear, an avoidance pattern — not external.

"Successful people always begin the analysis of constraints by asking: what is it in me that is holding me back?"

Find the constraint, address it directly, and your overall speed increases immediately.

### 14. Maximise Your Personal Power

Identify your peak energy hours — the time of day when you are most alert, focused, and effective. Protect these hours ruthlessly for your most important work. Never spend peak hours on email, admin, meetings, or anything that does not require your best thinking.

"It is the quality of time at work that counts and the quantity of time at home that matters."

Eat well, sleep enough, and exercise regularly. Your physical energy is the foundation for your mental energy. Neglecting it costs far more in lost productivity than the time it takes to maintain it.

### 15. Motivate Yourself into Action

No one is coming to rescue you. The world is full of people waiting for someone else to motivate them. It does not work that way. You are responsible for your own emotional state and your own forward movement.

"Most of your emotions, positive or negative, are determined by how you talk to yourself on a minute-to-minute basis. It is not what happens to you but the way that you interpret things that determines how you feel."

Choose your self-talk deliberately. Stay positive and forward-looking. When you feel resistance, say to yourself: back to work. Then begin.

### 16. Get Off Technology

Social media, email, news feeds, and aimless browsing are among the greatest destroyers of productive time in existence. They are designed to capture attention and hold it. Be deliberate about when you use them. Check email at set times rather than continuously. Protect your focused work blocks from all digital interruption.

Replace time lost to technology with reading, exercise, family, or anything that actually improves your life and moves you toward your goals.

### 17. Slice and Dice the Task

When a project feels too large to begin, break it into the smallest possible pieces. Identify just one piece you can start right now and begin on that alone. Do not think about the rest until the first piece is done.

This is related to the oil barrel technique but applied specifically to projects with many moving parts. A report becomes an outline. An outline becomes a first paragraph. A first paragraph becomes the first sentence. Start anywhere. The act of starting is what matters.

### 18. Create Large Blocks of Time

Your most important creative and analytical work requires sustained, uninterrupted concentration. Schedule blocks of sixty to ninety minutes for deep work. Close the door, silence notifications, and work without stopping until the block is complete.

Batch similar smaller tasks — calls, emails, admin — into their own blocks outside of your peak hours. This prevents the constant task-switching that destroys both focus and momentum.

### 19. Develop a Sense of Urgency

Effective people move fast. They launch directly into their most important task and work steadily and single-mindedly until it is complete. Failure to execute is one of the biggest productivity problems in any organisation and in any individual life.

Develop the habit of acting quickly on your priorities. Speed is a competitive advantage. A bias toward action, even imperfect action, produces more results than careful deliberation that never leads anywhere.

### 20. Single Handle Every Task

Once you start your most important task, keep going until it is one hundred percent complete. No switching, no checking your phone, no side conversations, no distractions of any kind. Each time you stop and restart a task, you waste significant time and mental energy rebuilding your focus and context.

When you feel the pull to stop, say to yourself: back to work. Then continue.

"Single handling requires that once you begin, you keep working at the task without diversion or distraction until the job is 100 percent complete."

### 21. Zero-Based Thinking

Regularly ask yourself about every commitment, project, and activity in your life: if I were not already doing this, knowing what I know now, would I choose to start doing it today? If the answer is no, it is a candidate for stopping.

Apply this to projects, relationships, habits, recurring meetings, subscriptions, and obligations. Most people continue doing things long after the original reason has gone, simply out of inertia. Zero-based thinking cuts through that inertia and frees up time, energy, and attention for what actually matters now.

"Practice zero-based thinking in every part of your life."



## Daily Power Habits

Evening — write your daily list for tomorrow. Label every task with the ABCDE method before you sleep. Know what your A1 task is before the day begins. Your subconscious will begin preparing overnight.

Morning — start your A1 task immediately, before email, before messages, before anything else. Work on it without stopping until it is complete. This one habit alone will put you ahead of most people.

Throughout the day — when you complete a task, return to your list, identify the next highest-priority item, and begin immediately. Never let yourself drift into low-value activity because the obvious next step feels hard.

Weekly — review your key result areas, your three most important goals, and your master list. Ask: what one skill, if I improved it, would make the biggest difference? Commit to working on it.



## Quotes Worth Keeping

"Your ability to choose between the important and the unimportant is the key determinant of your success in life and work."

"One of the very worst uses of time is to do something very well that need not be done at all."

"Everyone procrastinates. The difference between high performers and low performers is largely determined by what they choose to procrastinate on."

"An average person who develops the habit of setting clear priorities and getting important tasks done quickly will run circles around a genius who makes wonderful plans but gets very little done."

"The hardest part of any important task is getting started. Once you actually begin work on a valuable task, you seem to be naturally motivated to continue."

"Continuous learning is the minimum requirement for success in any field."

"The world is full of people waiting for someone to come along and motivate them. The problem is that no one is coming to the rescue."



## How This Connects to Goals!

[Goals!](/blog/goals-by-brian-tracy) tells you what to achieve and builds the inner architecture to pursue it seriously. Eat That Frog tells you how to stop procrastinating and execute every single day.

- [Goals!](/blog/goals-by-brian-tracy) is the strategy — Eat That Frog is the daily discipline
- The 3P Formula programs the mind — the ABCDE Method organises the day
- The 6P Formula creates the plan — single-handling gets individual tasks finished
- Mindstorming generates solutions — eating the frog ensures you act on them

Read [Goals!](/blog/goals-by-brian-tracy) to know where you are going. Use Eat That Frog every day to make sure you are actually moving.

Eat That Frog! by Brian Tracy



# PRISM: Discover the Colors of Your Working Style

*Four colors, a handful of questions, and — if you answer honestly — a genuinely fresh perspective on why you react the way you do at work and in life.*



Most personality tools sort people into categories, slap on a label, and leave you with a description that's hard to act on. PRISM works differently. It doesn't tell you who you *are* — it tells you how you *operate* under pressure, in your natural environment, in professional relationships. And that distinction makes an enormous practical difference.

This article is a hands-on introduction to the PRISM methodology: what it is, where it comes from, how to read your results, and — most importantly — how to put that knowledge to work every day.



## What Is PRISM?

PRISM Brain Mapping is a psychometric tool grounded in neuroscience — specifically in understanding how different areas of the brain influence our behavior. The name comes from the analogy of an optical prism: white light splits into its component colors. Your personality works the same way. It's made up of different behavioral "colors" that combine into a unique profile.

Unlike many personality assessments, PRISM distinguishes between **natural behavior** (how you act when there's no pressure and no one is watching) and **adapted behavior** (how you adjust to meet the expectations of your environment). The gap between these two layers is often where the most valuable insights live — and it answers the question of why we feel like a different person at work than we do at home.

> "There is no good or bad PRISM profile. There are profiles that fit a given context — and profiles that don't."



## The Four Colors — A Practical Guide

Each color represents a set of motivations, values, and typical behaviors. One important note: almost everyone carries all four colors. What differs is the proportion — not whether a color is present or absent.

### 🟢 Green — The Harmonizer

Empathetic, patient, loyal. Green is motivated by care for others and the need for stable relationships. In a team, they are the glue — smoothing conflicts, listening deeply, remembering the human side of every situation. Green builds trust more slowly than other styles, but once built, it lasts.

Thrives in: harmony, predictability, a sense of belonging.
Struggles with: conflict, sudden change, competitive environments.

### 🔵 Blue — The Analyst

Precise, systematic, cautious. Blue is motivated by data and accuracy. Before making a decision, they want to understand all the variables. Quality and thoroughness are their core values — and they expect the same from others. Blue isn't afraid to say "I don't know yet," because getting it right matters more than getting it fast.

Thrives in: clear standards, time to analyze, the ability to refine details.
Struggles with: improvisation, missing data, pressure to decide without sufficient information.

### 🔴 Red — The Driver

Decisive, direct, results-oriented. Red is motivated by control and achievement. They act fast, dislike unnecessary procedures, and value efficiency over consensus. Red sees the goal and instinctively asks: *"what's in the way, and how do we remove it?"* In meetings, they often push to close discussions — the decision feels obvious to them, even when others aren't there yet.

Thrives in: autonomy, pace, measurable results, challenge.
Struggles with: excessive process, lack of influence, slow-moving environments.

### 🟡 Yellow — The Expresser

Enthusiastic, creative, sociable. Yellow is motivated by recognition and self-expression. They think in big pictures, are naturally infectious with energy, and spontaneously build bridges between people and ideas. Yellow often has the best idea in the room — and may need support from a more structured partner to actually see it through.

Thrives in: variety, creative freedom, visibility, human connection.
Struggles with: routine, isolation, excessive detail and control.



## How to Read Your Results

When you receive your profile, you'll see a distribution of the four colors — usually expressed as percentages or as a count of responses. Here's how to approach the interpretation:

**Step 1 — Find your dominant color.** The highest-scoring color describes your natural default mode: how you react under stress, how you make instinctive decisions, and what you need to feel good at work.

**Step 2 — Look at the configuration, not just the leader.** A green-yellow profile is something entirely different from a green-blue one, even if both have green on top. Your second-strongest color significantly shapes your operating style — it influences your pace, your priorities, and the way you communicate.

**Step 3 — Notice your lowest color.** The color with the lowest score isn't a weakness — it's simply an area where you operate less frequently and with less natural energy. In some roles this is entirely neutral. In others, it can create blind spots worth paying attention to.

**Step 4 — Map it against your professional context.** Ask yourself: what behaviors does my role actually require? Where does my profile work in my favor — and where do I have to consciously invest extra energy? This question matters more than the score itself.

> A practical note: shorter versions of the test (8–12 questions) give a useful directional picture of your dominant colors. They're a good starting point for reflection, but they don't replace a full assessment — especially in a professional or coaching context.



## Common Combinations Worth Knowing

The pairing of your two strongest colors often tells you more than the dominant color alone. A few common configurations:

**Red + Blue** — Fast decisions backed by data. A natural operational leader, effective in environments that demand both execution and precision. Watch out for: overlooking the human factor, difficulty slowing down to truly listen.

**Green + Yellow** — Builds authentic relationships, leads through atmosphere and warmth. An excellent mentor and transformational leader. Watch out for: avoiding difficult conversations, delaying decisions in the name of harmony.

**Blue + Green** — Attentive, reliable, consistent. Cares equally about quality and people. Watch out for: decisions that take too long, discomfort with ambiguity and open-ended situations.

**Yellow + Red** — Energetic, visionary, persuasive. A natural champion of new ideas and change. Watch out for: losing track of details and follow-through, difficulty working within constraints.

**Green + Blue** — An empathetic analyst. Builds trust through competence and consistency. Watch out for: difficulty with visibility and self-promotion — their work speaks quietly, even when it should speak loudly.



## How to Put This Into Practice

### Working with yourself

The most valuable question after taking the test isn't "what color am I?" — it's: *in which situations does my profile work for me, and in which does it cost me extra effort?* This isn't an invitation to fix yourself. It's a map of the terrain you navigate every day.

If your dominant color is blue, you naturally avoid situations where data is missing and control feels out of reach. Knowing this, you can consciously build "certainty rituals" — a quick review of the key numbers before an important meeting, rather than walking in with a vague sense of unease.

If green dominates, you may notice you put off difficult conversations far too long. Simply recognizing that pattern — without judging it — gives you the awareness to act sooner when the situation demands it.

### In relationships with others

PRISM is a remarkably useful tool for understanding why someone's working style frustrates you. A red charging ahead to a decision irritates a blue who hasn't finished analyzing. A green who wants to process feelings exasperates a red who considers that a detour. This isn't a personality flaw on either side — it's a difference in how the brain processes information and decides what matters.

A practical exercise: before entering a difficult conversation with someone who has a different profile, ask yourself — *what does this person need in order to feel heard and safe in this conversation?* Red needs specifics and respect for their time. Green needs you not to bulldoze. Blue wants data and space to ask questions. Yellow needs to feel seen, not just listened to.

### Building a team

One of the most powerful applications of PRISM is thinking deliberately about complementarity. Homogeneous team profiles — say, everyone is analytical — perform brilliantly under certain conditions and fall apart in others. A team that spans different colors, and understands its own differences, is dramatically more resilient and creative.

As a leader, it's worth knowing not just your own profile, but which colors are underrepresented on your team. Not to "hire by color," but to recognize which perspectives you need to actively seek out — because no one will bring them naturally.

### Managing your own career

PRISM can help answer one of the hardest career questions: *why does this role exhaust me, even though I'm good at it?* Often the answer lies here — the role requires you to operate against your natural profile, day after day. That's not a reason to quit, but it is a reason to understand the cost and manage it consciously.



## What PRISM Is Not

It's worth ending with a few caveats, because tools like this are easy to misuse.

PRISM is not a verdict. A profile describes tendencies, not fixed behavior. People with identical color distributions can live and work in completely different ways — because experience, values, and self-awareness all matter enormously.

PRISM should not be used to box people in. "She's green, so she can't lead" is a mistake. Every color has its own leadership style and its own strengths in that role.

PRISM does not replace conversation. A test result is a starting point for reflection, not a ready-made answer. The most valuable insights emerge when you test your result against reality — against feedback from others, against specific situations from your own life, alongside a coach or mentor. For more on coaching as a discipline, see [Coaching for Performance](/blog/coaching-for-performance) and the foundational ideas behind it in [The Inner Game](/blog/inner-game).



## A Final Thought

If I were to suggest one exercise after reading this article, it wouldn't be "go take the test." It would be this: recall three recent situations where you reacted in a way that surprised you — or surprised someone else. Consider which color was at the wheel in that moment. And ask yourself whether that was the color you *wanted* there.

Self-awareness isn't a weekend project. But PRISM can be a surprisingly good place to start.


Prism


# Goals! — Brian Tracy

Tracy wrote this after years of studying why some people achieve extraordinary things while others with equal ability achieve very little. The answer, consistently, was goals. Not talent, not luck, not connections — the habit of setting clear written goals and working on them every day.

## The Core Idea

Most people drift. They have vague wishes — to be happy, to earn more, to get fit — but no system for turning those wishes into reality. Tracy's argument is simple: your outer world is a reflection of your inner world. What you think about, plan for, and act on consistently is what your life becomes.

"Living without clear goals is like driving in a thick fog. No matter how powerful or well-engineered your car, you drive slowly, hesitantly, making little progress on even the smoothest road."

---

## Part One — Get Your Mindset Right

Do this work before setting a single goal. Most goal-setting fails here.

### 1. Unlock Your Potential

You have more natural potential than you could use in several lifetimes. Most people operate at a fraction of their capacity not because they lack ability, but because they have never been shown how to access it. The starting point is to accept, genuinely and completely, that you are capable of far more than you have yet achieved.

"The potential of the average person is like a huge ocean unsailed, a new continent unexplored, a world of possibilities waiting to be released and channeled toward some great good."

### 2. Take Charge of Your Life — Accept Total Responsibility

Stop blaming circumstances, other people, or bad luck. You are exactly where your choices have brought you. Nothing changes until you own that completely, with no excuses and no blame. This is not a comfortable idea but it is the most liberating one in the book.

"The happiest people in the world are those who feel absolutely terrific about themselves, and this is the natural outgrowth of accepting total responsibility for every part of their life."

### 3. Create Your Own Future

Imagine your ideal life five years from now with no constraints — what would it look like? Tracy calls this the magic wand exercise: if you could wave a magic wand and have your life be perfect in every area, what would it look like? Write it down. People who think long-term and hold a clear picture of where they are going consistently make better daily decisions than those living reactively.

### 4. Clarify Your Values

Before setting goals, know what actually matters to you — not what your parents wanted, not what society expects. What do you genuinely stand for? Goals built on someone else's values never last because the motivation underneath them is borrowed. Values are the foundation. Build everything on top of them.

### 5. Determine Your True Goals

Most people have never sat down and honestly asked: what do I really want? In every area of life — work, finances, health, relationships, personal development. Do not let any area drift on autopilot. Write it all out. This exercise alone, done thoroughly, produces clarity that most people never experience.

### 6. Decide Upon Your Major Definite Purpose

Of all your goals, one matters more than the others. Tracy calls it your Major Definite Purpose — the single goal that, if achieved, would do more to improve your life than anything else. Find it. Once identified, organise your daily activities around it. Everything else becomes secondary.

"Your ability to set goals is the master skill of success. Goals unlock your positive mind and release ideas and energy for goal attainment. Without goals, you simply drift and flow on the currents of life. With goals, you fly like an arrow, straight and true to your target."

### 7. Analyze Your Beliefs

Your strongly held beliefs act as a filter for everything you perceive and everything you attempt. If you believe you cannot do something, you will not try, or you will sabotage the attempt. Catch self-limiting beliefs and question them directly: is this actually true, or is this a story I inherited and never examined? Act as if you already have the quality you want to develop. Behaviour shapes belief just as much as belief shapes behaviour.

### 8. Use the 3P Affirmation Formula

Tracy's affirmations are not wishful thinking — they are deliberate instructions from the conscious mind to the subconscious. Every affirmation must be Personal, Positive, and Present tense.

- Start with I — "I am confident, disciplined, and focused"
- State what you want, never what you want to avoid
- Speak it as already true — "I earn X per month"
- Morning ritual: "I like myself and I love my work" — repeat until you mean it

---

## Part Two — The 21-Chapter Action System

### Step 1. Start at the Beginning — Write It Down

Be ruthlessly specific. A wish is vague. A goal is precise, measurable, and time-bound.

"A goal is something distinctly different from a wish. It is clear, written, and specific. It can be quickly and easily described to another person. You can measure it, and you know when you have achieved it or not."

Spend five minutes every morning writing your 10 to 15 most important goals in the present tense as if already achieved. This single habit, done consistently, will change what you accomplish.

"Goals in writing are dreams with deadlines."

Also write your goals in the evening before sleep. Your subconscious then works on them overnight.

### Step 2. Measure Your Progress — Assess Your Starting Point

Know exactly where you are now. Be honest about the habits, relationships, and patterns that have produced your current results. You cannot navigate to a destination without knowing your starting point. Set intermediate milestones so you know whether you are on track. What gets measured gets improved.

### Step 3. Find Your Why — List Every Reason

For each goal, write every reason you want it. The strength of your motivation is proportional to the number and depth of your reasons. When obstacles appear — and they will — your reasons are what keep you moving.

"The key to success is to focus our conscious mind on things we desire, not things we fear."

### Step 4. Set a Deadline

A goal without a deadline has no urgency, no beginning, no end. Assign a specific date. If you miss it, set a new one immediately. The deadline is not a judgment — it is a mechanism for creating forward motion.

### Step 5. Remove the Roadblocks — Identify Your Biggest Obstacle

Ask: what is the one thing standing between me and this goal? In most cases the honest answer is internal — a habit, a fear, a skill gap, a belief. Find it and name it. Removing the primary obstacle typically unlocks progress faster than any other action.

"Obstacles are what you see when you take your eyes off your goals."

### Step 6. Become an Expert in Your Field

The world pays exceptional rewards to people who are exceptionally good at what they do. Dedicate yourself to lifelong learning in your field. Read for one hour every day. Attend seminars. Listen to educational material when driving. Identify the one skill that, if you developed it to excellence, would have the greatest impact on your results — and work on it deliberately every day.

### Step 7. Associate with the Right People

You become like the people you spend most time with. Actively seek out people who are where you want to be, who are positive, goal-oriented, and ambitious. Reduce time with people who are negative, directionless, or who discourage your ambitions. Mentors and mastermind groups accelerate progress dramatically.

### Step 8. Make a Plan of Action — Apply the 6P Formula

"Proper Prior Planning Prevents Poor Performance."

Before you begin working toward any goal, write your plan on paper. Organise tasks by priority and sequence. Know what needs to happen before what else can happen. Every minute of planning saves ten minutes in execution.

- Write the plan before you begin, not during
- Prioritise ruthlessly — most important tasks first, always
- Review and adjust as you go, but keep moving

### Step 9. Manage Your Time Well

Time is your most precious and irreplaceable resource. Every minute spent on a low-value activity is a minute stolen from a high-value one. Apply the 80/20 rule constantly — 20% of your activities produce 80% of your results. Identify that 20% and protect time for it. Learn to say no to everything that does not move you toward your Major Definite Purpose.

"If what you are doing is not moving you toward your goals, then it is moving you away from them."

### Step 10. Review Your Goals Daily

Review your written goals every morning when you begin your day, and again every evening. Read them out loud. This daily review keeps your goals alive in your conscious mind and feeds them continuously into your subconscious, which works on them around the clock.

"When you rewrite and review your goals in the evening, your subconscious mind then has an opportunity to work on your goals all night long while you are sleeping."

### Step 11. Visualise Your Goals Continually

Create clear, vivid, emotional mental pictures of your goals as already achieved. See yourself in the picture. Feel the emotions of having accomplished it. The more sensorially rich and emotionally charged the mental image, the more powerfully it is accepted by the subconscious as an instruction. Combine visualisation with your 3P affirmations for maximum effect.

### Step 12. Activate Your Superconscious Mind

Tracy distinguishes three levels of mind: the conscious, the subconscious, and the superconscious. The superconscious is a higher creative intelligence that goes beyond ordinary thinking — the source of insight, intuition, sudden breakthroughs, and inspiration that arrives apparently from nowhere. It activates when you have a clear goal, intense desire, and a relaxed, optimistic mental state.

"Your superconscious mind operates best when you are in a mental state of calm, confident, relaxed expectation."

"Worry is a form of negative goal-setting."

To access it: write your goal clearly, affirm it, visualise it, then release it and get busy with action. The moment you stop straining after the answer and simply move forward, the superconscious delivers solutions.

### Step 13. Remain Flexible at All Times

Be absolutely clear about your goals and absolutely flexible about how you get there. The path from here to your goal is rarely the one you originally planned. New information arrives. Circumstances change. The person who insists on the original route when the road is blocked wastes time. The person who adjusts the method while holding firm to the destination keeps moving.

The only real question to ask about your current approach is: does it work? If yes, continue. If no, change something. There is no failure — only feedback.

"Be clear about your goal but be flexible about the process of achieving it."

### Step 14. Unlock Your Inborn Creativity — Mindstorming

You are more creative than you know. Creative ability is not fixed — it expands with use. Every problem contains a solution, and your mind is capable of generating it if given the right conditions.

The most powerful technique Tracy offers here is Mindstorming, also called the 20 Idea Method.

How to do it:

- Take a clean sheet of paper
- Write your goal or problem as a question at the top — specific and simple: "How can I double my income in the next twelve months?"
- Force yourself to write 20 answers to that question — without stopping, without judging
- Write each answer using the 3P Formula — personal, positive, present tense
- The first few answers will be obvious. The answers from 10 onwards will surprise you
- Take the best answer and act on it immediately

The discipline of generating 20 answers forces the mind past its comfortable, obvious responses into genuinely new territory. Do this for every major goal and every significant obstacle.

### Step 15. Do Something Every Day

The daily habit of action toward your goal is more important than the size of any single action. Something every day — however small — keeps momentum alive, signals to your subconscious that this goal is real and current, and compounds over time into results that seem extraordinary from the outside.

"Develop a sense of urgency. Get into the habit of moving fast on your goals."

### Step 16. Persist Until You Succeed

Every great achievement required persistence through setbacks, disappointments, and failures that most observers never see. Persistence is not stubbornness — it is the decision, made in advance, that you will not stop. Each time you persist through a difficulty you become stronger, more capable, and more certain that you will eventually succeed.

"Resolve in advance that no matter what happens, you will never give up. Persistence is self-discipline in action."

"The only guarantee of failure is to stop."

---

## Daily Power Habits

These are the practical rituals that hold the whole system together.

Morning — write your goals in present tense, speak your 3P affirmations, spend two minutes visualising your most important goal as already achieved. This programs your entire day before anything external interferes.

Evening — rewrite your goals, plan tomorrow using the 6P formula, review your priority task list before you sleep. Your subconscious works on problems overnight.

Mindstorming session — whenever you face an obstacle or need new ideas, take 20 minutes and generate 20 written answers to a specific question. Act on the best one immediately.

Keep goals private — do not announce them before you have results. Telling people too early dissipates energy and invites discouragement.

Apply the 80/20 rule everywhere — 20% of your actions produce 80% of your results. Identify and protect that 20%.

[Eat the frog](/blog/eat-that-frog-by-brian-tracy) first — your hardest, most important task first every morning.

---

## Quotes Worth Keeping

"A goal is something distinctly different from a wish. It is clear, written, and specific. You can measure it, and you know when you have achieved it or not."

"Goals in writing are dreams with deadlines."

"You become what you think about most of the time. Your outer world ultimately becomes a reflection of your inner world."

"People with clear, written goals accomplish far more in a shorter period of time than people without them could ever imagine."

"Obstacles are what you see when you take your eyes off your goals."

"If what you are doing is not moving you toward your goals, then it is moving you away from them."

"Be clear about your goal but be flexible about the process of achieving it."

"The act of taking the first step is what separates the winners from the losers."

"Resolve in advance that no matter what happens, you will never give up. Persistence is self-discipline in action."



Goals! by Brian Tracy


# Shape Up by Ryan Singer - Book Review

Shape Up is a game-changing book about product development written by Ryan Singer from Basecamp. The book presents a methodology for running software projects that focuses on shipping valuable features in defined time periods.

## Key Concepts

### The Problem with Traditional Agile
Traditional agile methodologies often lead to:
- Never-ending backlogs
- Constant pressure to estimate work accurately
- Teams feeling overwhelmed with too many priorities
- Stakeholders losing trust in delivery timelines

### Shape Up's Solution
Shape Up introduces a different approach:

1. **Fixed Time Periods**: Work is organized in 6-week cycles followed by 2-week cooldown periods
2. **Problem-Based Planning**: Instead of detailed requirements, teams work on solving specific problems
3. **Betting**: Stakeholders place bets on which projects will deliver the most value
4. **Scope Control**: Teams have the authority to adjust scope to fit the timeframe

## The Cycle Structure

### 6-Week Cycles
During the main cycle, teams focus on shipping defined features without interruption. The fixed timeframe creates natural constraints that force good decisions about scope and complexity.

### 2-Week Cooldowns
Cooldown periods are for:
- Bug fixes and maintenance
- Technical debt reduction
- Research and exploration for the next cycle
- Team improvement and learning

## Practical Implementation

### Appetite vs Estimates
Instead of detailed estimates, teams define their "appetite" - how much effort they're willing to invest in solving a problem. This approach:
- Removes the pressure of perfect estimation
- Encourages creative problem-solving
- Focuses on value delivery rather than task completion

### The Pitch Process
Project pitches include:
- The problem being solved
- Proposed solutions
- Success criteria
- Appetite level
- Potential risks

## My Takeaways

After implementing Shape Up principles, I've observed:

1. **Better Focus**: Teams concentrate on fewer things and deliver more value
2. **Improved Stakeholder Trust**: Predictable cycles build confidence in delivery
3. **Healthier Work Environment**: Cooldown periods prevent burnout
4. **Better Solutions**: Problem-based thinking leads to more creative solutions

## Who Should Read This Book

Shape Up is essential reading for:
- Product managers and product owners
- Engineering managers and team leads
- Startup founders and executives
- Anyone frustrated with traditional agile implementations

## Final Thoughts

Shape Up isn't just another methodology—it's a fundamental shift in how we think about software development. By focusing on problems instead of features, and using time as a constraint rather than a resource to optimize, we can build better products in healthier, more sustainable ways.

The book is well-written, practical, and filled with real examples from Basecamp's experience. Whether you're struggling with your current agile implementation or just looking for ways to improve your product development process, Shape Up provides valuable insights that can transform how your team works.

If you're also interested in the leadership side of running engineering teams, see [Become an Effective Software Engineering Manager](/blog/become-an-effective-software-engineering-manager).


Book review: Shape Up by Ryan Singer


# Become an Effective Software Engineering Manager - Book Review

Making the transition from individual contributor to engineering manager is one of the most challenging career moves in tech. This book provides a comprehensive guide for navigating this transformation successfully.

## The Transition Challenge

Moving from writing code to leading people requires a fundamental mindset shift. Many new managers make the mistake of trying to be the "best programmer on the team" when their real value comes from enabling others to do their best work.

## Key Areas Covered

### 1. Mindset Shift
The book emphasizes that engineering management isn't about being the most technical person in the room. Instead, it's about:
- Creating an environment where engineers can do their best work
- Removing obstacles and providing clear direction
- Developing talent and building strong teams
- Making strategic decisions that align with business goals

### 2. People Management
Effective people management involves:
- **1-on-1s**: Regular, meaningful conversations about career growth, challenges, and feedback
- **Performance Management**: Setting clear expectations and providing constructive feedback
- **Team Building**: Creating psychological safety and fostering collaboration
- **Conflict Resolution**: Addressing issues before they escalate

### 3. Technical Leadership
Even as managers, we need to maintain technical credibility:
- Understanding the technical challenges your team faces
- Making informed architectural decisions
- Balancing technical debt with feature delivery
- Staying current with technology trends

### 4. Project Management
The book covers practical approaches to:
- Roadmap planning and execution
- Resource allocation and team capacity
- Risk management and mitigation
- Stakeholder communication and expectation management

## Practical Frameworks

### The Manager's Calendar
Effective time management is crucial. The book suggests:
- **Strategic Time**: Planning, thinking, and decision-making
- **People Time**: 1-on-1s, team meetings, career discussions
- **Administrative Time**: Reporting, process management, coordination
- **Technical Time**: Code reviews, architecture discussions, staying current

### Feedback Frameworks
Giving and receiving feedback effectively:
- **SBI Model**: Situation-Behavior-Impact
- **Regular cadence**: Don't save feedback for performance reviews
- **Two-way communication**: Be open to feedback about your management style

## My Key Takeaways

### 1. Your Success = Your Team's Success
The most important realization is that as a manager, your success is measured by your team's achievements, not your individual contributions.

### 2. Context Switching is Real
Managing requires constant context switching between technical discussions, people issues, strategic planning, and administrative tasks. Building systems to handle this effectively is crucial.

### 3. Communication is Your Primary Tool
Clear communication becomes your most important skill. Whether it's setting expectations, giving feedback, or representing your team to stakeholders, effective communication drives everything.

### 4. Develop Your Leadership Style
There's no one-size-fits-all approach to management. The book encourages developing your authentic leadership style while learning from others' experiences.

## Common Pitfalls to Avoid

### 1. The Technical Crutch
Don't hide behind technical work when faced with difficult people decisions.

### 2. Being the Bottleneck
Avoid becoming the decision bottleneck for your team. Empower them to make decisions.

### 3. Neglecting Your Own Development
Focus on your team's growth, but don't forget to invest in your own development as a manager.

### 4. Isolation
Management can be lonely. Build networks with other managers and find mentors.

## Who Should Read This Book

This book is essential for:
- New engineering managers transitioning from IC roles
- Experienced managers looking to improve their practice
- Senior engineers considering management careers
- Engineering leaders wanting to build better management systems

## Final Thoughts

"Become an Effective Software Engineering Manager" provides a solid foundation for the challenging transition into engineering management. It balances theory with practical advice and real-world examples.

The book acknowledges that there's no perfect formula for management success, but it provides frameworks and approaches that can be adapted to different contexts and leadership styles.

For anyone making or considering the move into engineering management, this book is an invaluable resource that will help you navigate the challenges and build a successful management career.

If you're interested in the people side of leadership, see also [Coaching for Performance](/blog/coaching-for-performance) and [PRISM](/blog/prism) for understanding different working styles. For a fresh take on running software projects, check out [Shape Up](/blog/shape-up-book-review).


Book review: Become an Effective Software Engineering Manager


# New Year's Resolutions for 2024

As we step into 2024, I'm taking time to reflect on the past year and set meaningful intentions for the year ahead. This year, I'm focusing on sustainable growth rather than ambitious but unrealistic goals.

## Professional Development

### Deepen Technical Skills
- **Advanced TypeScript**: Move beyond basic types to advanced patterns and generics
- **Performance Optimization**: Deep dive into web performance metrics and optimization techniques
- **Architecture Patterns**: Study distributed systems and microservices architecture
- **AI/ML Integration**: Explore how to effectively integrate AI tools into development workflows

### Leadership Growth
- **Mentoring**: Formal mentorship relationships with junior developers
- **Public Speaking**: Present at least one technical conference or meetup
- **Writing**: Publish technical blog posts monthly to share knowledge
- **Strategic Thinking**: Develop better product and business acumen

## Personal Development

### Health & Wellness
- **Consistent Exercise**: 4-5 workouts per week, mixing strength training and cardio
- **Better Sleep**: Target 7-8 hours of quality sleep nightly
- **Mindfulness**: Daily meditation practice, even if just 10 minutes
- **Nutrition**: Meal prep and reduce processed food intake

### Learning & Growth
- **Read 24 Books**: Two books per month, mixing technical and non-technical content
- **Learn a New Skill**: Pick up a new programming language or framework
- **Language Practice**: Continue improving my English fluency
- **Creative Projects**: Work on personal coding projects outside of work

## Work-Life Balance

### Boundaries
- **Defined Work Hours**: Stick to consistent start and end times
- **Weekend Disconnection**: No work-related activities on weekends
- **Vacation Time**: Take all vacation days without checking work messages
- **Digital Detox**: Regular periods without screens or notifications

### Relationships
- **Quality Time**: Dedicated time with family and friends
- **Networking**: Regular catch-ups with professional contacts
- **Community**: Participate in local tech community events
- **Family Activities**: Plan regular family outings and activities

## Financial Goals

### Investment & Savings
- **Increase Savings Rate**: Aim for 20% savings rate
- **Investment Education**: Learn more about different investment strategies
- **Side Projects**: Explore monetization opportunities for personal projects
- **Financial Planning**: Review and adjust long-term financial goals

## Approach to Resolutions

### The Problem with Traditional Resolutions
Traditional New Year's resolutions often fail because:
- They're too ambitious and unsustainable
- They focus on outcomes rather than systems
- They don't account for life's unpredictability
- They lack flexibility and adaptation

### My 2024 Strategy
This year, I'm trying a different approach:

1. **Systems Over Goals**: Focus on daily habits and systems rather than end results (see also [Goals! by Brian Tracy](/blog/goals-by-brian-tracy) for a complete goal-setting system and [Eat That Frog!](/blog/eat-that-frog-by-brian-tracy) for the daily execution discipline)
2. **Quarterly Reviews**: Review and adjust goals every quarter
3. **Flexibility**: Allow for changes based on life circumstances
4. **Accountability**: Share goals with trusted friends for accountability
5. **Celebration**: Acknowledge progress, not just completion

### Tracking Progress
I'll use:
- **Weekly Check-ins**: Brief review of progress and challenges
- **Monthly Reflections**: Deeper analysis of what's working and what isn't
- **Quarterly Adjustments**: Modify goals based on learnings and priorities
- **Annual Review**: Comprehensive year-end assessment

## Specific Focus Areas for Q1 2024

### January: Foundation Building
- Establish daily routines and habits
- Set up tracking systems for all goals
- Complete one technical certification course
- Start the reading challenge

### February: Momentum Building
- Maintain established habits
- Begin mentorship relationships
- Submit first conference talk proposal
- Start first personal project

### March: First Quarter Review
- Assess progress on all goals
- Adjust strategies based on learnings
- Plan Q2 objectives
- Celebrate early wins

## Final Thoughts

The key to successful resolutions isn't perfection—it's consistency and self-compassion. Some goals will be achieved, others will be modified, and some will be abandoned. That's okay.

What matters is the intention to grow, the willingness to try, and the courage to adjust course when needed. Here's to a year of meaningful progress, sustainable growth, and balance.

Happy New Year 2024! May it bring you growth, joy, and success in all your endeavors.


New Year's resolutions for 2024


# Coaching for performance

Following are notes i took while reading this book at the beginning of 2023.

"Coaching for Performance" is definitely one of the top 5 professional books I have read in recent years. I would recommend it to everyone, regardless of their position within the company hierarchy. The core message of the book is to increase awareness of our daily responsibilities, enhance communication, and accomplish goals that benefit not only the organizations we are part of but also our personal well-being. The book emphasizes the importance of "being true to oneself and fully utilizing one's potential."

When reading this book I came across the diagram that visually shows how awareness and responsibility are keys to building high-performing organizations.

Additionally, the author suggests the various models used to scale up and grow companies have little value without the context of awareness and responsibility and the right intentions and skills to generate them (eg. through active listening and powerful questions).

Hence, if you manage teams or decide on how your company runs you might want to consider it to make a real positive impact that is based on human growth and dignity.

In the 1970s, tennis coach Timothy Gallwey developed a number of concepts which contributed to the development of coaching, including the importance of awareness of internal obstacles (our thoughts, feelings, and physical reactions, which are often self-created). Gallwey recognized the power of increased awareness in decreasing performance-limiting interference. You can read more about this in my post on [The Inner Game](/blog/inner-game). He stated:

Our Performance equals our potential minus interference (P = p - i)


Coaching for performance


# Book review: Genius Makers

I'm not a big fan of non-fiction books and I made an exception for it as it's a subject closely related to my day-to-day work.

What I enjoyed is the fact that easy to read with a good tempo and gives you insight behind de scenes - at least this is my relative impression and I'm sure there are still many uncovered facts. Yet it keeps me intrigued and keen on finding out more about who was involved and what motivated them. Personally I score it 5/5

I don't think there is anything in particular that I don't like. If there was one thing I could request from the author would be to keep it up-to-date for the next years to come in the form of the appendix or new releases :) Who knows, maybe in a few years there will be a second part that will shed light on the current world situation (war in Ukraine, semiconductors race, COVID etc ) that shaped the state of AI.

To summarize it's a well-written report like a book that I'll be recommending it now to everyone. And I mean it. AI is having an impact on lives of all of us not only the IT sector, hence knowing a few facts about how it all started and developed over decades gives a better understanding of the current situation and key players on the stage.

[Direct link](https://www.amazon.com/Genius-Makers-Mavericks-Brought-Facebook/dp/1524742678)


Book review: Genius Makers


# Inner game

In the 1970s, tennis coach Timothy Gallwey developed a number of concepts which contributed to the development of coaching, including the importance of awareness of internal obstacles (our thoughts, feelings, and physical reactions, which are often self-created). Gallwey recognized the power of increased awareness in decreasing performance-limiting interference. He stated:


Inner game



This is part 2 of the Interview series. See also [Part 1: CSS, HTML & Accessibility](/blog/interview-questions-part-1) and [Part 3: React](/blog/interview-questions-react).

## Core JavaScript Concepts

###accordion: What is an IIFE and why are they used?

An IIFE (Immediately Invoked Function Expression) is a function that runs as soon as it's defined:

```javascript
// Traditional IIFE
(function() {
  console.log("This runs immediately!");
})();

// Arrow function IIFE
(() => {
  console.log("Arrow IIFE too!");
})();

// With parameters
((name) => {
  console.log(`Hello, ${name}!`);
})("World");
```

**Why use IIFEs?**
- Create private scope and avoid polluting global namespace
- Execute initialization code immediately
- Module pattern implementation
- Async IIFEs for top-level await in older environments

###accordion: What is Closure?

A closure is a function that has access to variables in its outer (enclosing) scope even after the outer function has returned:

```javascript
function createCounter() {
  let count = 0; // This variable is "closed over"
  
  return function() {
    count++; // Still has access to count
    return count;
  };
}

const counter = createCounter();
console.log(counter()); // 1
console.log(counter()); // 2
console.log(counter()); // 3

// Practical example: private variables
function createBankAccount(initialBalance) {
  let balance = initialBalance;
  
  return {
    deposit: (amount) => {
      balance += amount;
      return balance;
    },
    withdraw: (amount) => {
      if (amount <= balance) {
        balance -= amount;
        return balance;
      }
      return "Insufficient funds";
    },
    getBalance: () => balance
  };
}
```

###accordion: Difference between var and let

**Scope:**
- `var` - Function scoped
- `let` - Block scoped (curly braces)

**Hoisting:**
- `var` - Hoisted with undefined initial value
- `let` - Hoisted but not initialized (TDZ)

**Re-declaration:**
- `var` - Can be re-declared
- `let` - Cannot be re-declared in same scope

```javascript
function testVar() {
  if (true) {
    var x = 1;
  }
  console.log(x); // 1 (function scoped)
}

function testLet() {
  if (true) {
    let y = 1;
  }
  console.log(y); // ReferenceError (block scoped)
}
```

###accordion: Difference between map, filter and reduce

**map:** Transforms each element, returns new array of same length

```javascript
const numbers = [1, 2, 3, 4];
const doubled = numbers.map(x => x * 2); // [2, 4, 6, 8]
```

**filter:** Returns elements that pass a condition

```javascript
const numbers = [1, 2, 3, 4, 5, 6];
const evens = numbers.filter(x => x % 2 === 0); // [2, 4, 6]
```

**reduce:** Reduces array to single value

```javascript
const numbers = [1, 2, 3, 4];
const sum = numbers.reduce((acc, x) => acc + x, 0); // 10

// Group by category
const people = [
  { name: 'Alice', age: 25, department: 'Engineering' },
  { name: 'Bob', age: 30, department: 'Engineering' },
  { name: 'Charlie', age: 35, department: 'Sales' }
];

const byDepartment = people.reduce((acc, person) => {
  const dept = person.department;
  if (!acc[dept]) acc[dept] = [];
  acc[dept].push(person);
  return acc;
}, {});
```

## Asynchronous JavaScript

###accordion: What are Promises?

A Promise represents the eventual completion (or failure) of an asynchronous operation:

```javascript
// Creating a promise
const fetchData = () => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      const success = true;
      if (success) {
        resolve({ data: "Some data", timestamp: Date.now() });
      } else {
        reject(new Error("Failed to fetch data"));
      }
    }, 1000);
  });
};

// Using promises
fetchData()
  .then(result => {
    console.log("Success:", result);
    return result.data;
  })
  .then(data => {
    console.log("Processed:", data);
  })
  .catch(error => {
    console.error("Error:", error.message);
  })
  .finally(() => {
    console.log("Cleanup");
  });

// Promise methods
Promise.all([fetchData(), fetchData()])
  .then(results => console.log("All done", results));

Promise.race([fetchData(), timeout(500)])
  .then(result => console.log("First completed", result));
```

###accordion: Async/Await

Syntactic sugar for working with promises:

```javascript
// Async function
async function fetchUserData(userId) {
  try {
    const response = await fetch(`/api/users/${userId}`);
    const user = await response.json();
    
    const posts = await fetch(`/api/users/${userId}/posts`);
    const userPosts = await posts.json();
    
    return { user, posts: userPosts };
  } catch (error) {
    console.error("Failed to fetch user data:", error);
    throw error;
  }
}

// Using async/await
const userData = await fetchUserData(123);

// Parallel execution with Promise.all
async function fetchMultipleUsers(userIds) {
  const promises = userIds.map(id => fetchUserData(id));
  const results = await Promise.all(promises);
  return results;
}

// Error handling
async function example() {
  try {
    await riskyOperation();
  } catch (error) {
    // Handle error
  } finally {
    // Always runs
  }
}
```

## JavaScript Fundamentals

###accordion: What's the difference between null, undefined or undeclared?

**undefined:** Variable declared but not assigned

```javascript
let x;
console.log(x); // undefined
console.log(typeof x); // "undefined"
```

**null:** Explicit absence of value

```javascript
let y = null;
console.log(y); // null
console.log(typeof y); // "object" (JavaScript bug)
```

**undeclared:** Variable never declared

```javascript
console.log(z); // ReferenceError: z is not defined
```

**Best practices:**
- Use `undefined` for "no value yet"
- Use `null` for "intentionally empty"
- Always declare variables to avoid undeclared errors

###accordion: What is the 'this' keyword and how is it used?

`this` refers to the execution context:

```javascript
// Global context
console.log(this); // Window object (in browser)

// Function context
function showThis() {
  console.log(this);
}
showThis(); // Window (non-strict) or undefined (strict)

// Method context
const obj = {
  name: "Object",
  showThis() {
    console.log(this.name); // "Object"
  }
};

// Constructor context
function Person(name) {
  this.name = name; // Refers to new instance
}

// Arrow function context
const arrowObj = {
  name: "Object",
  showThis: () => {
    console.log(this.name); // undefined (inherits from outer scope)
  }
};

// Explicit binding
const person = { name: "John" };
function greet() {
  console.log(`Hello, ${this.name}!`);
}
greet.call(person); // "Hello, John!"
greet.apply(person); // "Hello, John!"
const boundGreet = greet.bind(person);
boundGreet(); // "Hello, John!"
```

## Coding Challenges

###accordion: Write function that checks if the number is prime

```javascript
function isPrime(n) {
  // Handle edge cases
  if (n <= 1) return false;
  if (n <= 3) return true;
  if (n % 2 === 0 || n % 3 === 0) return false;
  
  // Check divisors up to sqrt(n)
  for (let i = 5; i * i <= n; i += 6) {
    if (n % i === 0 || n % (i + 2) === 0) {
      return false;
    }
  }
  
  return true;
}

// Test cases
console.log(isPrime(2));   // true
console.log(isPrime(17));  // true
console.log(isPrime(25));  // false
console.log(isPrime(97));  // true

// Optimized version with memoization
const isPrimeMemo = (() => {
  const cache = new Map();
  
  return (n) => {
    if (cache.has(n)) return cache.get(n);
    
    let result;
    if (n <= 1) result = false;
    else if (n <= 3) result = true;
    else if (n % 2 === 0 || n % 3 === 0) result = false;
    else {
      result = true;
      for (let i = 5; i * i <= n; i += 6) {
        if (n % i === 0 || n % (i + 2) === 0) {
          result = false;
          break;
        }
      }
    }
    
    cache.set(n, result);
    return result;
  };
})();
```

###accordion: FizzBuzz

```javascript
// Classic FizzBuzz solution
function fizzBuzz(n) {
  const result = [];
  
  for (let i = 1; i <= n; i++) {
    if (i % 15 === 0) {
      result.push("FizzBuzz");
    } else if (i % 3 === 0) {
      result.push("Fizz");
    } else if (i % 5 === 0) {
      result.push("Buzz");
    } else {
      result.push(i.toString());
    }
  }
  
  return result;
}

// Functional approach
const fizzBuzzFunctional = (n) => 
  Array.from({ length: n }, (_, i) => i + 1)
    .map(num => {
      const fizz = num % 3 === 0 ? "Fizz" : "";
      const buzz = num % 5 === 0 ? "Buzz" : "";
      return fizz + buzz || num.toString();
    });

// One-liner (for interviews)
const fizzBuzzOneLiner = (n) => 
  [...Array(n).keys()].map(i => {
    i++;
    return (i % 15 ? i % 3 ? i % 5 ? i : "Buzz" : "Fizz" : "FizzBuzz");
  });

// Test
console.log(fizzBuzz(15));
// ["1", "2", "Fizz", "4", "Buzz", "Fizz", "7", "8", "Fizz", "Buzz", "11", "Fizz", "13", "14", "FizzBuzz"]
```

## Additional JavaScript Topics

### List ES6 features

- Arrow functions
- Template literals
- Destructuring assignment
- Default parameters
- Rest and spread operators
- Let and const
- Classes
- Modules (import/export)
- Promises
- Symbol type
- Iterators and generators
- Map and Set data structures

### List JavaScript data types

**Primitive types:**
- Number
- String
- Boolean
- Undefined
- Null
- Symbol (ES6)
- BigInt (ES2020)

**Reference types:**
- Object
- Array
- Function
- Date
- RegExp
- Map, Set, WeakMap, WeakSet

### How JavaScript's runtime works? Describe an event loop mechanism

JavaScript runs on a single-threaded event loop:

1. **Call Stack:** Executes synchronous code
2. **Heap:** Memory allocation for objects
3. **Web APIs:** Browser APIs for async operations
4. **Callback Queue:** Queues callbacks from async operations
5. **Event Loop:** Moves callbacks from queue to stack when stack is empty

**How many threads does JavaScript have?**
- **Main thread:** 1 (single-threaded)
- **Web Workers:** Multiple additional threads for background processing

### What are Web Workers?

Web Workers allow running JavaScript in background threads:

```javascript
// main.js
const worker = new Worker('worker.js');
worker.postMessage('Hello from main');
worker.onmessage = function(e) {
  console.log('Message from worker:', e.data);
};

// worker.js
self.onmessage = function(e) {
  console.log('Message from main:', e.data);
  self.postMessage('Hello from worker');
};
```

**Benefits:**
- Run heavy computations without blocking UI
- True parallel processing
- Separate memory space

**Limitations:**
- No direct DOM access
- Limited access to Web APIs
- Communication via message passing

## Summary

This is part 2 of the Interview series. Continue with [Part 1: CSS, HTML & Accessibility](/blog/interview-questions-part-1) and [Part 3: React](/blog/interview-questions-react). You may also find [Popular Acronyms](/blog/popular-acronyms) useful for interview preparation.
## Revers string

## Useful link and resources

You may also find [Popular Acronyms](/blog/popular-acronyms) helpful — knowing YAGNI, KISS, DRY and SOLID comes up in interviews too.


Interview questions part 2: JavaScript



This is part 1 of the Interview series. See also [Part 2: JavaScript](/blog/interview-questions-javascript) and [Part 3: React](/blog/interview-questions-react).

## General Questions

###accordion: Tell me about your past/current role - what do you do?

I'm a frontend developer with X years of experience building responsive, accessible web applications. My role involves:

- Developing user interfaces using modern JavaScript frameworks like React/Vue
- Writing clean, maintainable CSS with methodologies like BEM or CSS-in-JS
- Ensuring cross-browser compatibility and accessibility compliance
- Collaborating with designers and backend developers to implement features
- Optimizing application performance and user experience
- Participating in code reviews and mentoring junior developers

###accordion: What is the typical workflow from the point you get a task to its completion?

My typical workflow follows these steps:

1. **Requirements Analysis:** Review task specifications and clarify any ambiguities with the product owner/designer
2. **Technical Planning:** Break down the task into smaller components, estimate effort, and identify potential challenges
3. **Environment Setup:** Create feature branch, set up local development environment
4. **Implementation:** Write code following best practices, including unit tests
5. **Self-Review:** Test the implementation, check for edge cases, ensure code quality
6. **Code Review:** Submit pull request and address feedback from team members
7. **Integration Testing:** Test in staging environment, ensure no regressions
8. **Deployment:** Merge to main branch and deploy to production
9. **Monitoring:** Monitor the feature post-deployment for any issues

###accordion: What tools and techniques do you use?

I use a variety of tools and techniques:

**Development Tools:**
- VS Code with extensions for ESLint, Prettier, GitLens
- Chrome DevTools for debugging and performance analysis
- Postman/Insomnia for API testing
- Figma for design collaboration

**Version Control:**
- Git with feature branch workflow
- Conventional commits for better commit history
- GitHub/GitLab for code review and CI/CD

**Performance Tools:**
- Lighthouse for performance auditing
- WebPageTest for detailed performance analysis
- Bundle analyzers for optimization

## HTML/CSS questions

###accordion: How we can optimize site loading time?

Site optimization involves multiple strategies:

**Network Optimization:**
- Enable HTTP/2 or HTTP/3 for multiplexing
- Use CDN for static assets
- Implement resource hints (preload, prefetch, preconnect)
- Minimize HTTP requests with bundling

**Asset Optimization:**
- Compress images (WebP format, responsive images)
- Minify CSS, JavaScript, and HTML
- Use lazy loading for images and components
- Implement service workers for caching

**Code Optimization:**
- Code splitting and tree shaking
- Remove unused CSS and JavaScript
- Optimize critical rendering path
- Use modern JavaScript features for better performance

###accordion: What units do you use px, em, or rem?

I use different units based on context:

**rem (root em):** My preferred unit for most sizing
- Consistent sizing relative to root font size
- Better accessibility (respects user's font size preferences)
- Easier to maintain consistent scale

**em:** Used when sizing needs to be relative to parent
- Components that should scale with their container
- Typography within specific contexts

**px:** Used sparingly for specific cases
- Border widths that shouldn't scale
- Pixel-perfect design requirements
- Media query breakpoints

**Viewport units (vw, vh):** For responsive layouts
- Full-width sections (100vw)
- Viewport-based typography

###accordion: What is the 'Box Model' in CSS?

The CSS Box Model describes how elements are rendered as rectangular boxes:

**Components (from inside out):**
1. **Content:** The actual content (text, images)
2. **Padding:** Space between content and border
3. **Border:** Goes around padding and content
4. **Margin:** Space outside the border (collapses with other margins)

**Box-Sizing Property:**

```css
/* Default: content-box */
.box-sizing-content {
  width: 200px; /* Only content width */
  padding: 20px; /* Adds to total width */
  border: 2px solid black; /* Adds to total width */
  /* Total width: 244px */
}

/* Modern: border-box */
.box-sizing-border {
  width: 200px; /* Includes padding and border */
  padding: 20px;
  border: 2px solid black;
  /* Total width: 200px */
}
```

###accordion: What's the difference between "resetting" and "normalizing" CSS?

**CSS Reset:**
- Removes all default styling from elements
- Creates a blank slate across all browsers
- Example: Eric Meyer's CSS Reset
- Pros: Complete control, consistent starting point
- Cons: Must re-style everything, can remove useful defaults

**CSS Normalize:**
- Makes browsers render elements consistently
- Preserves useful defaults while fixing inconsistencies
- Example: normalize.css
- Pros: Better accessibility, less work to restore defaults
- Cons: Some inconsistencies may remain

**My Choice:** I prefer normalize.css because it maintains useful browser defaults (like form styling) while ensuring consistency across browsers.

###accordion: How do you organise your CSS - Namespace patterns?

I use several organization strategies:

**BEM (Block Element Modifier):**
```css
.card { }
.card__header { }
.card__header--highlighted { }
```

**CSS Modules:**
- Scoped class names to avoid conflicts
- Component-based organization
- Clear dependency relationships

**Utility-First (Tailwind):**
- Consistent design system
- Rapid development
- Smaller CSS bundle through purging

**File Structure:**
```
styles/
  components/
    button.css
    card.css
  utilities/
    spacing.css
    colors.css
  base/
    reset.css
    typography.css
```

## Accessibility

###accordion: How can we improve form accessibility?

**Semantic HTML:**

```html
<form>
  <fieldset>
    <legend>Personal Information</legend>
    
    <label for="name">
      Name: <input type="text" id="name" required>
    </label>
    
    <label for="email">
      Email: <input type="email" id="email" required>
    </label>
  </fieldset>
</form>
```

**ARIA Enhancements:**
- Use aria-describedby for additional help text
- Add aria-invalid for validation errors
- Implement aria-live regions for dynamic updates

**Keyboard Navigation:**
- Ensure proper tab order
- Add focus indicators
- Implement keyboard shortcuts

**Error Handling:**
- Associate error messages with inputs
- Provide clear validation feedback
- Use aria-live for real-time validation

###accordion: List some of the Aria roles and explain when would you use them

**Landmark Roles:**
- `role="navigation"` - Main navigation blocks
- `role="main"` - Primary content area
- `role="banner"` - Header/site identity
- `role="contentinfo"` - Footer/copyright info
- `role="search"` - Search functionality

**Widget Roles:**
- `role="button"` - Interactive elements that aren't native buttons
- `role="dialog"` - Modal dialogs and popups
- `role="tablist"`, `role="tab"` - Tab interfaces
- `role="menu"`, `role="menuitem"` - Navigation menus

**Structure Roles:**
- `role="region"` - Related content sections
- `role="group"` - Grouped related controls
- `role="list"`, `role="listitem"` - List semantics

###accordion: How else would you improve site accessibility?

**Performance:**
- Optimize images and media for screen readers
- Ensure keyboard accessibility for all interactive elements
- Provide text alternatives for non-text content

**Navigation:**
- Skip links for keyboard users
- Consistent navigation patterns
- Clear heading structure (h1-h6 hierarchy)

**Content:**
- Use clear, simple language
- Provide transcripts for audio/video content
- Ensure sufficient color contrast (WCAG AA or AAA)

**Testing:**
- Regular accessibility audits
- Screen reader testing
- Keyboard-only navigation testing
- User testing with people with disabilities

## Useful Resources

- [MDN Web Docs](https://developer.mozilla.org/) - Comprehensive web development documentation
- [Web.dev](https://web.dev/) - Modern web development best practices
- [A11y Project](https://www.a11yproject.com/) - Accessibility guidelines and patterns
- [Can I Use](https://caniuse.com/) - Browser compatibility tables

## Summary

This is part 1 of the Interview series. Continue with [Part 2: JavaScript](/blog/interview-questions-javascript) and [Part 3: React](/blog/interview-questions-react). You may also find [Popular Acronyms](/blog/popular-acronyms) useful for interview preparation.


Interview questions part 1 - CSS, HTML & Accessibility



Welcome to 3rd post from the Interview series. If you missed the earlier parts, start with [Part 1: CSS, HTML & Accessibility](/blog/interview-questions-part-1) and [Part 2: JavaScript](/blog/interview-questions-javascript). This time I'd like to focus on questions around React and its ecosystem.

## Core React Concepts

###accordion: What is virtual DOM and how does React use it to render to the DOM?

The Virtual DOM is a JavaScript representation of the real DOM:

```javascript
// Virtual DOM representation (simplified)
const vdom = {
  type: 'div',
  props: { className: 'container' },
  children: [
    { type: 'h1', props: {}, children: ['Hello'] },
    { type: 'p', props: {}, children: ['World'] }
  ]
};
```

**How React uses it:**
1. **Render:** Create Virtual DOM representation
2. **Reconciliation:** Compare new VDOM with previous VDOM
3. **Commit:** Update only changed parts of real DOM

**Benefits:**
- Performance: Batch DOM updates
- Declarative: Describe desired state, React handles updates
- Cross-platform: Same code works for React Native

###accordion: What is JSX?

JSX is a syntax extension for JavaScript that allows HTML-like code in JS:

```javascript
// JSX syntax
const element = <h1 className="greeting">Hello, world!</h1>;

// Compiled to JavaScript
const element = React.createElement(
  'h1',
  {className: 'greeting'},
  'Hello, world!'
);

// Component with JSX
function Welcome({ name }) {
  return <div>
    <h1>Hello, {name}</h1>
    {name === 'Admin' && <p>Administrator access</p>}
  </div>;
}

// Expressions in JSX
const items = ['Apple', 'Banana', 'Orange'];
const list = <ul>
  {items.map(item => <li key={item}>{item}</li>)}
</ul>;
```

**Key points:**
- Compiles to React.createElement() calls
- Must have one root element (or Fragment)
- Use className instead of class
- JavaScript expressions in curly braces

###accordion: What problems does React solve?

**UI Complexity:**
- Manages complex state changes
- Prevents direct DOM manipulation
- Declarative vs imperative programming

**Performance:**
- Virtual DOM for efficient updates
- Batched DOM operations
- Component-based architecture

**Maintainability:**
- Reusable components
- Clear data flow (props down, events up)
- Separation of concerns

**Ecosystem:**
- Large community and ecosystem
- Extensive tooling support
- Cross-platform (React Native)

###accordion: What are the pros and cons of using React?

**Pros:**
- **Large ecosystem:** Huge community, many libraries
- **Performance:** Virtual DOM, efficient updates
- **Reusable components:** DRY principle
- **Tooling:** Excellent developer tools
- **Job market:** High demand for React developers
- **Flexibility:** Works with various backends and architectures

**Cons:**
- **Learning curve:** JSX, state management, lifecycle
- **Fast-paced:** Frequent updates, deprecations
- **Boilerplate:** Setup can be complex
- **Opinionated:** React way vs vanilla JavaScript
- **Bundle size:** Can be large if not optimized
- **State management:** No built-in solution

## React Components and Styling

###accordion: How do you style components in React?

**1. CSS Modules:**

```css
/* Button.module.css */
.button {
  background: blue;
  color: white;
  padding: 10px;
}
```

```javascript
// Button.js
import styles from './Button.module.css';
function Button() {
  return <button className={styles.button}>Click me</button>;
}
```

**2. Styled Components:**

```javascript
import styled from 'styled-components';

const Button = styled.button`
  background: ${props => props.primary ? 'blue' : 'gray'};
  color: white;
  padding: 10px;
`;

<Button primary>Primary</Button>
```

**3. Tailwind CSS:**

```javascript
function Button({ primary }) {
  return (
    <button className={`px-4 py-2 rounded ${primary ? 'bg-blue-500' : 'bg-gray-500'}`}>
      Click me
    </button>
  );
}
```

**4. Inline Styles:**

```javascript
function Button({ primary }) {
  const style = {
    background: primary ? 'blue' : 'gray',
    color: 'white',
    padding: '10px'
  };
  return <button style={style}>Click me</button>;
}
```

###accordion: What features were introduced in React 16.x?

- **Fragments:** Wrap multiple elements without extra DOM nodes
- **Error Boundaries:** Catch JavaScript errors in component trees
- **Portals:** Render children into different DOM subtree
- **Custom DOM Attributes:** Pass non-standard HTML attributes
- **Improved Server Rendering:** Faster server-side rendering
- **Context API:** Simplified context without Provider/Consumer nesting
- **React.memo:** Pure component memoization
- **Lazy Loading:** Code splitting with React.lazy()
- **Suspense:** Handle async components loading

###accordion: What are Higher Order Components?

HOCs are functions that take a component and return a new component:

```javascript
// HOC that adds logging
function withLogging(WrappedComponent) {
  return function WithLoggingComponent(props) {
    console.log('Rendering:', WrappedComponent.name);
    return <WrappedComponent {...props} />;
  };
}

// HOC that adds data fetching
function withDataFetching(url) {
  return function(WrappedComponent) {
    return functionWithDataFetching(props) {
      const [data, setData] = useState(null);
      const [loading, setLoading] = useState(true);

      useEffect(() => {
        fetch(url)
          .then(res => res.json())
          .then(data => {
            setData(data);
            setLoading(false);
          });
      }, []);

      if (loading) return <div>Loading...</div>;
      return <WrappedComponent data={data} {...props} />;
    };
  };
}

// Usage
const LoggedInButton = withLogging(Button);
const UserListWithData = withDataFetching('/api/users')(UserList);
```

## State Management

###accordion: What's the difference between state and props?

**Props:**
- Read-only data passed from parent to child
- Immutable (cannot be modified by child)
- Flow data down the component tree
- Used for component configuration

**State:**
- Mutable data managed within component
- Can be changed using setState or useState
- Triggers re-renders when updated
- Used for dynamic data and user interactions

```javascript
function UserProfile({ name, age }) { // Props
  const [isEditing, setIsEditing] = useState(false); // State
  
  return (
    <div>
      <h2>{name}, {age}</h2>
      <button onClick={() => setIsEditing(!isEditing)}>
        {isEditing ? 'Save' : 'Edit'}
      </button>
    </div>
  );
}
```

###accordion: State management in React apps: what are the options?

**1. Local State (useState/useReducer):**
- Component-level state
- Simple to implement
- Good for UI-specific state

**2. Context API:**
- Built-in React solution
- Avoids prop drilling
- Good for global state

```javascript
const UserContext = createContext();

function App() {
  const [user, setUser] = useState(null);
  return (
    <UserContext.Provider value={{ user, setUser }}>
      <Layout />
    </UserContext.Provider>
  );
}
```

**3. Redux:**
- Predictable state container
- Great for large applications
- Steep learning curve

**4. Zustand:**
- Lightweight state management
- Simple API
- Good balance of features

**5. Recoil/Jotai:**
- Atomic state management
- Fine-grained reactivity
- Modern approach

###accordion: What is prop drilling and how can you avoid it?

**Prop drilling:** Passing props through multiple levels of components that don't need them:

```javascript
// Prop drilling example
function App() {
  const [user, setUser] = useState(null);
  return <Layout user={user} />;
}

function Layout({ user }) {
  return <Header user={user} />;
}

function Header({ user }) {
  return <UserAvatar user={user} />; // Only Avatar needs user
}

function UserAvatar({ user }) {
  return <img src={user.avatar} alt={user.name} />;
}
```

**Solutions to avoid prop drilling:**

**1. Context API:**
```javascript
const UserContext = createContext();

function App() {
  const [user, setUser] = useState(null);
  return (
    <UserContext.Provider value={{ user, setUser }}>
      <Layout />
    </UserContext.Provider>
  );
}

function UserAvatar() {
  const { user } = useContext(UserContext);
  return <img src={user.avatar} alt={user.name} />;
}
```

**2. State Management (Redux/Zustand):**
```javascript
// Zustand example
import { create } from 'zustand';

const useUserStore = create(set => ({
  user: null,
  setUser: (user) => set({ user })
}));

function UserAvatar() {
  const user = useUserStore(state => state.user);
  return <img src={user.avatar} alt={user.name} />;
}
```

**3. Component Composition:**
```javascript
function App() {
  const [user, setUser] = useState(null);
  return (
    <Layout>
      <Header>
        <UserAvatar user={user} />
      </Header>
    </Layout>
  );
}
```

## React Hooks

###accordion: What are hooks and why are they useful?

Hooks allow using state and lifecycle features in functional components:

```javascript
// useState hook
import { useState } from 'react';

function Counter() {
  const [count, setCount] = useState(0);
  
  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>Increment</button>
    </div>
  );
}

// useEffect hook
import { useState, useEffect } from 'react';

function Timer() {
  const [seconds, setSeconds] = useState(0);
  
  useEffect(() => {
    const interval = setInterval(() => {
      setSeconds(s => s + 1);
    }, 1000);
    
    return () => clearInterval(interval); // Cleanup
  }, []);
  
  return <div>Seconds: {seconds}</div>;
}

// Custom hook
function useCounter(initialValue = 0) {
  const [count, setCount] = useState(initialValue);
  
  const increment = () => setCount(count + 1);
  const decrement = () => setCount(count - 1);
  const reset = () => setCount(initialValue);
  
  return { count, increment, decrement, reset };
}
```

**Benefits:**
- No need for class components
- Better code organization
- Reusable logic (custom hooks)
- Easier testing and reasoning

## React Performance and Best Practices

###accordion: Why React requires key to render the list?

Keys help React identify which items have changed, been added, or removed:

```javascript
// Without keys (problematic)
function TodoList({ items }) {
  return (
    <ul>
      {items.map(item => (
        <li>{item.text}</li> // React can't track individual items
      ))}
    </ul>
  );
}

// With keys (correct)
function TodoList({ items }) {
  return (
    <ul>
      {items.map(item => (
        <li key={item.id}>{item.text}</li> // React can track items
      ))}
    </ul>
  );
}
```

**Why keys are important:**
- **Performance:** React can reuse DOM nodes
- **State preservation:** Component state stays with correct item
- **Animations:** Smooth transitions when order changes

**Key requirements:**
- Must be unique among siblings
- Should be stable (don't use Math.random())
- Use IDs, array indexes (last resort), or generated keys

```javascript
// Good: using unique IDs
items.map(item => <li key={item.id}>{item.text}</li>)

// Bad: using index (can cause issues with reordering)
items.map((item, index) => <li key={index}>{item.text}</li>)
```

###accordion: How can we improve Accessibility in React?

**Semantic JSX:**
```javascript
function Form() {
  return (
    <form>
      <fieldset>
        <legend>Personal Information</legend>
        <label htmlFor="name">Name:</label>
        <input id="name" type="text" required />
      </fieldset>
    </form>
  );
}
```

**ARIA Attributes:**
```javascript
function Modal({ isOpen, onClose, children }) {
  return (
    <div 
      role="dialog" 
      aria-modal="true"
      aria-labelledby="modal-title"
    >
      <h2 id="modal-title">Modal Title</h2>
      {children}
      <button onClick={onClose}>Close</button>
    </div>
  );
}
```

**Keyboard Navigation:**
```javascript
function FocusableButton({ children, onClick }) {
  const ref = useRef(null);
  
  const handleKeyDown = (e) => {
    if (e.key === 'Enter' || e.key === ' ') {
      onClick();
    }
  };
  
  return (
    <button
      ref={ref}
      onKeyDown={handleKeyDown}
      onClick={onClick}
    >
      {children}
    </button>
  );
}
```

**Accessibility Testing:**
- Use React Testing Library with jest-axe
- Test with screen readers
- Keyboard navigation testing

## React Ecosystem

###accordion: What is Redux?

Redux is a predictable state container for JavaScript applications:

```javascript
// Action
const increment = () => ({ type: 'INCREMENT' });

// Reducer
function counterReducer(state = { count: 0 }, action) {
  switch (action.type) {
    case 'INCREMENT':
      return { count: state.count + 1 };
    default:
      return state;
  }
}

// Store
import { createStore } from 'redux';
const store = createStore(counterReducer);

// Component
import { useSelector, useDispatch } from 'react-redux';

function Counter() {
  const count = useSelector(state => state.count);
  const dispatch = useDispatch();
  
  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => dispatch(increment())}>Increment</button>
    </div>
  );
}
```

**Core Concepts:**
- **Store:** Single source of truth
- **Actions:** Describe what happened
- **Reducers:** Specify how state changes
- **Middleware:** Extend Redux functionality

###accordion: What solution would you use to process asynchronous requests with Redux?

**Redux Thunk:**
```javascript
import { createAsyncThunk } from '@reduxjs/toolkit';

const fetchUser = createAsyncThunk(
  'user/fetchUser',
  async (userId) => {
    const response = await api.fetchUser(userId);
    return response.data;
  }
);
```

**Redux Saga:**
```javascript
import { takeEvery, call, put } from 'redux-saga/effects';

function* fetchUser(action) {
  try {
    const user = yield call(api.fetchUser, action.payload);
    yield put({ type: 'FETCH_USER_SUCCESS', payload: user });
  } catch (error) {
    yield put({ type: 'FETCH_USER_ERROR', payload: error });
  }
}

function* userSaga() {
  yield takeEvery('FETCH_USER_REQUEST', fetchUser);
}
```

**RTK Query (Recommended):**
```javascript
import { createApi, fetchBaseQuery } from '@reduxjs/toolkit/query/react';

export const api = createApi({
  reducerPath: 'api',
  baseQuery: fetchBaseQuery({ baseUrl: '/api/' }),
  endpoints: (builder) => ({
    getUser: builder.query({
      query: (id) => `users/${id}`,
    }),
  }),
});

export const { useGetUserQuery } = api;
```

###accordion: What is Next.js?

Next.js is a React framework for production:

**Features:**
- **Server-Side Rendering (SSR):** Better SEO and performance
- **Static Site Generation (SSG):** Pre-built pages
- **Incremental Static Regeneration (ISR):** Update static content
- **API Routes:** Backend API in Next.js
- **File-based routing:** Simple routing system
- **Image optimization:** Built-in image component
- **Code splitting:** Automatic optimization

```javascript
// pages/index.js - SSR
export async function getServerSideProps(context) {
  const data = await fetchData();
  return { props: { data } };
}

// pages/blog/[slug].js - SSG
export async function getStaticProps({ params }) {
  const post = await getPost(params.slug);
  return { props: { post } };
}

// pages/api/users.js - API Route
export default function handler(req, res) {
  res.status(200).json({ users: [] });
}
```

## Testing

###accordion: How do you unit test a React Component?

**Using React Testing Library:**

```javascript
import { render, screen, fireEvent } from '@testing-library/react';
import Counter from './Counter';

describe('Counter', () => {
  test('renders initial count', () => {
    render(<Counter />);
    expect(screen.getByText('Count: 0')).toBeInTheDocument();
  });

  test('increments count when button clicked', () => {
    render(<Counter />);
    const button = screen.getByText('Increment');
    
    fireEvent.click(button);
    expect(screen.getByText('Count: 1')).toBeInTheDocument();
  });

  test('calls callback when count changes', () => {
    const onCountChange = jest.fn();
    render(<Counter onCountChange={onCountChange} />);
    
    fireEvent.click(screen.getByText('Increment'));
    expect(onCountChange).toHaveBeenCalledWith(1);
  });
});
```

**Testing Hooks:**
```javascript
import { renderHook, act } from '@testing-library/react';
import useCounter from './useCounter';

test('useCounter increments correctly', () => {
  const { result } = renderHook(() => useCounter());
  
  act(() => {
    result.current.increment();
  });
  
  expect(result.current.count).toBe(1);
});
```

###accordion: What is Jest?

Jest is a JavaScript testing framework:

**Features:**
- Zero configuration setup
- Built-in assertion library
- Mocking capabilities
- Code coverage reporting
- Snapshot testing

**Example:**
```javascript
// sum.test.js
import sum from './sum';

test('adds 1 + 2 to equal 3', () => {
  expect(sum(1, 2)).toBe(3);
});

test('object assignment', () => {
  const data = { one: 1 };
  data['two'] = 2;
  expect(data).toEqual({ one: 1, two: 2 });
});

test('null', () => {
  const n = null;
  expect(n).toBeNull();
  expect(n).toBeDefined();
  expect(n).not.toBeUndefined();
});
```

## Useful Resources

- [React Documentation](https://react.dev/) - Official React docs and tutorials
- [React Patterns](https://reactpatterns.com/) - Common React patterns and best practices
- [React Testing Library](https://testing-library.com/docs/react-testing-library/intro/) - Testing React components
- [React Performance](https://react.dev/learn/render-and-commit) - Understanding React's rendering process

## Summary

This is part 3 of the Interview series. Continue with [Part 1: CSS, HTML & Accessibility](/blog/interview-questions-part-1) and [Part 2: JavaScript](/blog/interview-questions-javascript). You may also find [Popular Acronyms](/blog/popular-acronyms) useful for interview preparation.


Interview questions: React


# Introduction to Web3

Web3 applications run on blockchains, decentralized networks of many peer to peer nodes, or a combination of the two that forms a crypto economic protocol. These apps are often referred to as dapps (decentralized apps). Web3 changes how we architect and interact with applications from the ground up. You can find more from this article by Nader Dabit.

[Direct link](https://www.freecodecamp.org/news/what-is-web3/)


Introduction to Web3


# New Generation of Build Tools

After a couple of years where one could think the build tools settle down around Webpack, Rollup, or Parcel now we are going into another wave. Tools such as Vite, ESbuild or Snowpack are new rising stars with a great focus on bundle times. They also fill a missing middle ground between the writing conveniences of writing a single JavaScript file and the need to download hundreds of megabytes of dependencies before you've written a line of your own code.

[Direct link](https://css-tricks.com/comparing-the-new-generation-of-build-tools/)


New Generation of Build Tools


# Popular Acronyms

## Welcome to my third post.

I must admit that I start to enjoy writing more than ever before and I hope I'll keep momentum.

This time I'd like to focus on acronyms that are commonly used in software engineering. Most likely you already develop using some of the principles that are represented here without even being aware of it.

There are quite a few acronyms commonly used in software methodologies. Some less serious than others (eg. HDD - Hype Driven Development) but in this article, I'd like to focus only on the following 4:

```
HDD
```

Y.A.G.N.I., K.I.S.S., D.R.Y., & S.O.L.I.D. Knowing those will help you not only write better code but also during the [interview process](/blog/interview-questions-part-1) where you might be asked to decode either the entire shortening or particular letter.

Do not confuse acronyms with abbreviations as some sites/articles do as those two are quite distinct.
- Abbreviation form new words eg Dr for Doctor
- acronym typically contains a set of initial letters eg. ASAP As Soon As Possible

```
Dr
```


```
ASAP
```

## Y.A.G.N.I - You Ain't Gonna Need It

YAGNI is a principle of Extreme Programming (XP) that sets that a programmer should not add functionality until deemed necessary. In my view, this principle should go before the K.I.S.S principle where you should think twice if you really going to need certain functionality if yes keep it simple.

## K.I.S.S - Keep it Simple, Stupid

## D.R.Y - Don't Repeat Yourself

## S.O.L.I.D

## Useful resources:


Popular Acronyms


# Welcome

Welcome to my blog and my first ever public post. I'm a web developer with more than 10 years of commercial experience but all the post I had written were in fact Confluence documentation for project and features I had a chance to work on.

Having my own blog was my dream for around 2-3 years but I never was brave enough to start sharing my thoughts with the moreover wider group. I was afraid (and still am) if my written English is good enough if what I write about will be clear and easy to understand and more over if I find subjects that will be not only interesting for me but also for others. Simply I was overcomplicating it in my own head.

Today I'm finally changing it. While working on the new layout I've decided it is the right moment to introduce a new section - Blog. I have refactored my personal website to use NextJs and Vercel with local markdown content. Thanks to markdown-based content management, publishing new content is simple and the experience is clean and efficient.

What pushed me to start blogging was the infamous year 2020.

It was thought but also it helped me to realise that as husband and father of 3 I need to be stronger. Not only physically but also mentally. Also as a father I'm responsible for well being of my closes family which is reflected in having quality time with them but also provide financial security so when another pandemic hits it won't have a bad impact on us.

Hence this year I started with listening to podcasts around self-development (Dominik Juszczyk), reading about finances ([Finansowa forteca](https://finansowaforteca.pl/)) and pay more attention to my health.

As a result, I decided to drop alcohol (at least until Jan 2022), start working out regularly and create so-called financial pillows by saving money, long term investments using ETFs, plan for next 12 weeks rather than a whole year. But real game change was discovering "Life S.A.V.E.R.S" which is an acronym used by Hal Elrod in his book called "[The Miracle Morning](https://www.amazon.com/gp/product/0979019710/)" and it stands for Silence (meditation/praying), Affirmations, Visualisations, Exercise, Reading and Scribing (writing a journal). If affirmations and visualisation resonate with you, [Goals! by Brian Tracy](/blog/goals-by-brian-tracy) takes these ideas much further with a complete goal-setting system. You can read more about this method on Hal's website

And this blog is a natural outcome of the last point (Scribing) and all the changes that started to happen in my life this year. After encouraged by starting my personal diary something has clicked in my head and I have opened myself to go public with writing.

I plan to blog about all sorts of things from web development to self-development. From investing to book reviews. And more.

Who knows what the future holds. But for now, I want to leave you with one quote from [Essentialism](https://gregmckeown.com/books/essentialism/)book by Greg McKeown:


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