Roadmap › 4. Frontend › Step 43
JS
JavaScript (ES5 → ES2025) & TypeScript Basics
Types, scope, hoisting, closures, this, prototypes, classes, the event loop, promises and async/await, modules, DOM and events, fetch, ES6+ features, error handling, performance, security and TypeScript essentials.
Interview priority:★ Must know High priority — asked in almost every interview, learn firstMedium asked regularlyLow good to know
Module 1: Language Basics
- 1.Data types, typeof and equalityBasic ★ Must know
- 2.var, let and const; scope and hoistingBasic ★ Must know
- 3.Functions: declarations, expressions, arrows, default/rest/spreadBasic ★ Must know
- 4.Arrays and objects — the essential methodsBasic ★ Must know
Module 2: Core Concepts
- 5.ClosuresIntermediate ★ Must know
- 6.The `this` keyword, call, apply and bindIntermediate ★ Must know
- 7.Prototypes, inheritance and classesIntermediate ★ Must know
- 8.The event loop, microtasks and macrotasksIntermediate ★ Must know
- 9.Promises and async/awaitIntermediate ★ Must know
- 10.Modules (ESM vs CommonJS)Intermediate Medium
Module 3: Browser and DOM
- 11.DOM manipulation and eventsBasic ★ Must know
- 12.Storage, fetch, CORS and browser APIsIntermediate Medium
- 13.Debounce, throttle, memoisation and other utilitiesIntermediate ★ Must know
Module 4: Advanced and TypeScript
- 14.Generators, iterators, Map/Set, WeakMap and ProxyAdvanced Medium
- 15.Memory leaks, performance and securityAdvanced Medium
- 16.TypeScript essentialsIntermediate ★ Must know
Next course in the roadmap: 44. TypeScript — Types, Generics and Real-World Patterns →