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Study guide · 8 topics

JavaScript Exam Study Guide

Eight topic guides covering everything tested on JavaScript interviews and exams. Code examples, exam traps, and tips throughout.

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01 · 6 min read

JavaScript var vs let vs const — Scope, Hoisting & TDZ Explained

var, let, and const behave very differently. Scope and hoisting questions appear in every JavaScript interview.

Read guide →02 · 6 min read

JavaScript Functions — Arrow Functions, this Keyword & bind/call/apply

The `this` keyword is one of the most misunderstood parts of JavaScript. Here's what interviews actually test.

Read guide →03 · 6 min read

JavaScript Array Methods — map, filter, reduce & More Explained

Array methods are tested in every JavaScript interview. Here's what you need to know — from map/filter/reduce to destructuring.

Read guide →04 · 7 min read

JavaScript Promises & async/await — Complete Guide with Examples

Asynchronous JavaScript is tested in every senior interview. Here's what you need to know — from callbacks to async/await.

Read guide →05 · 6 min read

JavaScript ES6+ Features — Destructuring, Spread, Modules & More

Modern JavaScript interviews expect ES6+ fluency. Here's what comes up most — destructuring, optional chaining, and modules.

Read guide →06 · 5 min read

JavaScript DOM Manipulation & Events — querySelector, addEventListener

DOM manipulation is a front-end interview staple. Here's what gets tested — from selecting elements to event delegation.

Read guide →07 · 6 min read

JavaScript Prototypes & Classes — Inheritance, extends & super

Prototypes underpin all JavaScript objects. Here's what interviews test — prototype chain, class syntax, and inheritance.

Read guide →08 · 5 min read

JavaScript Error Handling — try/catch, Custom Errors & Async Patterns

Error handling is essential for production code. Here's what interviews test — from try/catch to handling async errors properly.

Read guide →

Where JavaScript leads

Certifications that build on JavaScript

Real proctored exams with published blueprints — each with a free readiness test here that scores you per exam domain rather than giving you one number.

GitHub GH-600 (Agentic AI Developer)

Microsoft lists Developer among GH-600’s roles and asks for experience with the SDLC, GitHub workflows and code review. The exam tests running coding agents on a real repository, not a language.

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