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[JS] How I Fixed React’s Annoying Load Flickers

Hey 👋 お元気ですか？ What You Can Expect from This Post You ever load up your React app — and for a split second, everything’s just... blank? Or worse, elements pop in one by one — the background loads, then the avatar, then the UI buttons, and it feels like your app is

[JS] Why My React Component Is Re-Rendering Forever

Hey everyone 👋 お元気ですか？ Today I want to share something that once drove me crazy: “Why is my React component re-rendering infinitely!?” What You Can Expect from This Post At first, I thought maybe it was a bug in React. But of course — it wasn’t React’s fault. It was

[JS] Update State Based on Old State in React

Hello everyone, お元気ですか？ Today I want to talk about one of those sneaky little bugs that looks fine... until it doesn’t: updating state based on its previous value in React. What You Can Expect from This Post When I first started using useState, I thought updating state was as

[JS] Dynamically Set Properties in Object

What can be expected from this post? Let me share a small story from my recent coding adventure. I was building a simple two-player game in JavaScript. You know, the classic kind — one player is X, the other is O. Everything was going smoothly… until I wanted to let players

[Mind-Checkins] What I’ve Learned Rebuilding a React Game

Hello everyone, お元気ですか？ Today I want to share my experience with React. I was first exposed to it last year and built a few small apps. But since it was my first time learning React, I struggled with some of the syntax and core concepts. Later, I joined a bootcamp

[JS] Shallow Copy v.s. Deep Copy

What You Can Expect from This Post Recently, I was building a small browser game in JavaScript. The game had a board — just a simple array that changed every round depending on player actions. At the end of the game, I wanted to reset the board to its initial state

[JS] Mastering the Spread Operator: Unpack Arrays and Objects with Ease

What can be expected from this post? In a lot of javascript functions, you may see ... quite a lot. In this post, we’ll explore the JavaScript spread operator — the magical triple dots (...) that can help us pull out values from arrays and objects with ease. What Is the Spread

[JS] JavaScript Functions: myFunc vs myFunc() Explained Simply

What you can expect from this post? When I was learning JavaScript, one thing kept confusing me: We often need to pass a function into another function — like setTimeout or addEventListener — but sometimes we add parentheses () after the function name, and sometimes we don’t. How do we know when

[JS] Export v.s. Import Modules

What to Expect from This Post In this post, we’ll learn how to export and import variables between files in JavaScript using ES Modules (ESM). This is essential for writing modular, organized, and maintainable code. Folder Setup Example Let’s say we’re working with the following three files:

[Mind Check-ins] My first talk with recruiter in Japan

It has been one month since I graduated from Le Wagon bootcamp. Most of us have already started exploring job opportunities—and of course, I’m no exception. Thanks to Flo, whom I met at the alumni party, I was introduced to a recruiter named Andre. He’s originally from

[JS] Intersection Observer API

What’s the issue I spotted? While browsing modern websites, I noticed a common yet impressive feature: as I scroll to specific sections, those sections animate into view, and the corresponding item in the navigation bar becomes highlighted. This subtle interaction enhances the user experience dramatically. But that led me

[Leetcode] JS 30 Debounce

Question Given a function fn and a time in milliseconds t, return a debounced version of that function. A debounced function is a function whose execution is delayed by t milliseconds and whose execution is cancelled if it is called again within that window of time. The debounced function should

[Leetcode] JS 30 Cache With Time Limit

Question Write a class that allows getting and setting key-value pairs, however a time until expiration is associated with each key. The class has three public methods: set(key, value, duration): accepts an integer key, an integer value, and a duration in milliseconds. Once the duration has elapsed, the key

[Leetcode] JS 30 Promise Time Limit

Question Given an asynchronous function fn and a time t in milliseconds, return a new time limited version of the input function. fn takes arguments provided to the time limited function. The time limited function should follow these rules: * If the fn completes within the time limit of t milliseconds,