The Difference Between == and === in JavaScript
Compare == and === in JavaScript through type coercion, strict equality, surprising conversions, safer defaults, and when loose equality still appears.
Articles
JavaScript, page 16 of 17
JavaScript is probably one of the most‑used programming languages in the world, and a cornerstone of front‑end (and more general) web development. It enables the development of interactivity and features that HTML and CSS alone simply cannot, and includes more advanced concepts like closures, callbacks, and asynchronous programming.
Below you will find a subset of articles from my blog specifically about JavaScript. This is an area that I have worked with for many years, and have managed to write about quite a few times. There are three hundred collected together for you below.
The Difference Between == and === in JavaScript. The Difference Between
Classes in JavaScript: An Introduction. Classes in JavaScript: An Introduction
An article that provides a beginner‑friendly introduction to classes in JavaScript, explaining what they are, how they work, and how to use them in your code.
Comparing Arrays in JavaScript. Comparing Arrays in JavaScript
Comparing arrays in JavaScript is trickier than it first looks. This guide covers reference equality, value comparison, and practical alternatives.
Invoked Function Expressions (IIFE). Invoked Function Expressions (IIFE)
IIFEs were a common JavaScript pattern before modern modules took over. This guide explains what they do, why they existed, and when they still appear.
Understanding call, apply, and bind in JavaScript. Understanding
call,apply, andbindin JavaScriptUnderstand call, apply, and bind in JavaScript, including this context, argument passing, borrowed methods, invocation differences, and practical use.
Appending and Prepending Items to an Array. Appending and Prepending Items to an Array
Append and prepend array items in JavaScript with push(), unshift(), spread syntax, mutation trade‑offs, return values, and cleaner update patterns.
How Inheritance Works in the JavaScript Prototype Chain. How Inheritance Works in the JavaScript Prototype Chain
The JavaScript prototype chain underpins inheritance, enabling object property sharing. Here, I explore its workings, property searching, and quirks.
Type Coercion in JavaScript: Implicit vs. Explicit Conversion. Type Coercion in JavaScript: Implicit vs. Explicit Conversion
Type coercion in JavaScript explained clearly, including implicit vs. explicit conversion, equality surprises, string concatenation, and number casting.
Using CommonJS to Implement Modules in JavaScript. Using CommonJS to Implement Modules in JavaScript
Use CommonJS modules in JavaScript with require() and module.exports, covering Node.js origins, browser bundling, limitations, and ES module comparison.
Controlled vs. Uncontrolled Components in React. Controlled vs. Uncontrolled Components in React
Controlled vs. uncontrolled components in React explained with form examples, refs, validation trade‑offs, and why each approach suits different jobs.
Why this Changes in JavaScript Event Handlers and Methods. Why
thisChanges in JavaScript Event Handlers and MethodsUnderstand why this changes in JavaScript methods and event handlers, including call sites, arrow functions, bind(), event objects, and context bugs.
Looping in JavaScript ES5 and ES6: forEach and for...of. Looping in JavaScript ES5 and ES6:
forEachandfor...ofWith the introduction of the new JavaScript standard ES6, there are some new and interesting ways to loop through data, which I discuss here today.
Asynchronous Module Definition (AMD) in JavaScript. Asynchronous Module Definition (AMD) in JavaScript
Asynchronous Module Definition explained, including AMD module loading, define(), dependency handling, CommonJS, ES modules, and modern relevance.
Getting Started with Callbacks in JavaScript. Getting Started with Callbacks in JavaScript
Callbacks are a core part of JavaScript, even if promises get more attention now. This guide explains how they work and where they still show up.
Primitive vs. Reference Types in JavaScript. Primitive vs. Reference Types in JavaScript
Primitive vs. reference types in JavaScript explained clearly, including copying behaviour, mutation, equality, and why arrays and objects surprise beginners.
Lifting State up in React. Lifting State up in React
Lifting state up in React explained clearly, including shared state, single sources of truth, child callbacks, and when moving state higher helps.
Check If Your Site is Running on localhost. Check If Your Site is Running on
localhostThere are many reasons that you might want to detect whether your code is running on localhost. Aside from using environment variables, there's also JavaScript!
Dynamically Create a Script Element with JavaScript. Dynamically Create a Script Element with JavaScript
Create script elements dynamically with JavaScript, setting src, choosing head or body placement, loading external scripts, and understanding execution timing.
