🟨 JavaScript

What you can learn on this page

• What is JavaScript? — JavaScript is like a building's electrical wiring: HTML is the walls and floor, CSS is the paint and decor, JavaScript is the light switches, elevators, and automatic doors — the building reacts when a user touches something. Why does this matter? Because brow
• Installation & Setup — Step 1: Install Node.js JavaScript runs outside the browser thanks to the Node.js runtime. When you install Node.js on your computer, npm (Node Package Manager) is automatically installed as well. Node.js is basically Chrome's V8 engine packaged to run locally
• Variables & Operators — JavaScript's `var`, `let`, and `const` are like three different storage containers: `var` is a leaky bucket — its value can seep outside function boundaries (hoisting + function scope). `let` is a lidded box — the value is changeable but only accessible within
• Data Types & Functions — JavaScript data types split into two groups and understanding this distinction is critical in test automation. Primitive types (String, Number, Boolean, Null, Undefined, Symbol, BigInt) are like postage stamps: the value is carried on the stamp itself, and cop
• String, Numbers & Math — String and number manipulation is the daily bread of test automation: you read element text from the page, trim and normalize it, convert price strings to numbers, and write assertions. Template literals (backtick strings) dramatically simplify this — where Ja
• Array Methods (map, filter) — JavaScript array methods are like specialized stations on a factory assembly line: raw material enters, each station does its job, processed product comes out. `map()` is the painting station — transforms each element, count stays the same. `filter()` is the q
• Conditions & Loops — Conditionals and loops are the traffic lights and junction routing systems of automation code: `if/else` decides which road to take at an intersection, loops (`for`, `while`, `for...of`) let you travel the same road multiple times. Why does JavaScript have mul
• Event Loop & Asynchronous JS — Understanding JavaScript's Event Loop is essential for fixing timing issues in Playwright tests. JavaScript is single-threaded: only one operation can happen at a time — like queuing up at a store with a single cashier. But how does this single cashier manage