Competencies: Programming Languages > JavaScript & TypeScript

JavaScript Fundamentals

Variables, functions, objects, arrays, prototypes, closures, event loop

Critical

Frontend Developer, Full-Stack Developer

TypeScript Type System

Static types, interfaces, generics, union/intersection types, type guards

Critical

Frontend Developer, Full-Stack Developer, Backend Developer

Async JavaScript

Promises, async/await, callbacks, event loop, microtask queue

Critical

Frontend Developer, Full-Stack Developer

Node.js Runtime

Event-driven architecture, modules, npm/yarn, fs, http, streams, child_process

High

Backend Developer, Full-Stack Developer, DevOps Engineer

Modern ES Features

ES6+: arrow functions, destructuring, spread operator, modules, classes

Critical

Frontend Developer, Full-Stack Developer

Frontend Frameworks

React, Vue, Angular fundamentals, component lifecycle, state management

High

Frontend Developer, Full-Stack Developer

DOM & Browser APIs

DOM manipulation, events, fetch API, Web Storage, Web Workers

High

Frontend Developer, Full-Stack Developer

Testing JavaScript

Jest, Mocha, Vitest, testing-library, mocking, snapshot testing

High

Frontend Developer, Full-Stack Developer, QA Engineer

Build Tools

Webpack, Vite, esbuild, bundling, tree-shaking, code splitting

High

Frontend Developer, Full-Stack Developer

Package Management

npm, yarn, pnpm, package.json, lockfiles, workspaces, dependency auditing

High

Frontend Developer, Full-Stack Developer, DevOps Engineer

TypeScript Advanced

Conditional types, mapped types, template literals, declaration files

Medium

Frontend Developer, Full-Stack Developer

To be populated

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