What is JavaScript?

In depth

JavaScript was created in September 1995 by Brendan Eich at Netscape in 10 days — first named "Mocha", then "LiveScript", finally "JavaScript" to ride Java's popularity. In 2026 it is the world's most-used programming language (W3Techs: 98.7% of websites use it, 67M GitHub repos).

JavaScript's specification is ECMAScript, published by ECMA International. Major version history: ES5 (2009) — strict mode, JSON, Array methods (forEach, map, filter); ES6/ES2015 — landmark version: classes, arrow functions, let/const, template literals, destructuring, modules (import/export), promises; ES2017 — async/await; ES2020 — optional chaining (?.), nullish coalescing (??), BigInt; ES2022 — top-level await, class fields; ES2024 — Promise.withResolvers, RegExp v flag; ES2025 — Records, Tuples (proposal stage). ECMAScript has had an annual release cycle since 2015.

TypeScript — Microsoft (Anders Hejlsberg), 2012, a JavaScript "superset" + static typing + class-based OOP. In 2026 TypeScript is effectively default for serious products: 78% of React projects use TS (State of JS 2025), Vue 3 was built in TS, Angular is TS by default, Next.js 13+ recommends TS. Craftwebstudio codebase is 100% TS strict mode.

Frameworks landscape 2026: (1) React (Meta) — UI library, 220K stars, market leader; React 19 (Q4 2024) Server Actions + use() hook; (2) Vue (Evan You) — progressive framework, 210K stars, popular in China/US; Vue 3.4 Composition API + script setup; (3) Svelte (Rich Harris) — compile-time framework, smallest bundle; Svelte 5 (Q4 2024) runes + reactivity rewrite; (4) Solid (Ryan Carniato) — fine-grained reactivity, JSX; (5) Angular (Google) — full-featured enterprise framework, RxJS-heavy. Craftwebstudio recommendation — React + Next.js (Vercel ecosystem, Server Components, edge functions).

Runtimes: (1) Browser — Chrome V8 engine (also Edge, Brave), Safari JavaScriptCore, Firefox SpiderMonkey; (2) Node.js (Ryan Dahl, 2009) — V8 + libuv, server-side JS, npm package manager (2.5M packages); (3) Bun (Jarred Sumner, 2022) — Zig-based, faster than Node.js (4× cold start), npm-compatible; (4) Deno (Ryan Dahl, 2018) — secure-by-default, TypeScript-native, Web APIs; (5) Workers — Cloudflare Workers, Vercel Edge Runtime — V8 isolates for serverless. 2026 trend: Bun is growing fast (1.0 stable Sep 2023, 70K stars), Deno added npm compatibility in 2024.

Package management: npm (2010) — Node's official central registry; yarn (Facebook, 2016) — faster install + workspaces; pnpm (Zoltan Kochan, 2017) — content-addressable storage, disk-efficient (used by Craftwebstudio). In 2026 lock files: package-lock.json (npm), yarn.lock, pnpm-lock.yaml — committed to git for reproducible builds.

2026 best practices: (1) TypeScript strict mode by default; (2) ESLint + Prettier auto-format; (3) Vitest unit tests (replaces Jest in 70% of projects); (4) Playwright E2E (replaces Cypress in many cases); (5) bundle analyzer (rollup-plugin-visualizer or @next/bundle-analyzer); (6) tree-shake heavy libs (Lodash → individual imports, moment.js → date-fns); (7) dynamic imports for code splitting; (8) ServiceWorker + Workbox for PWAs. Performance baseline: total JS bundle <200KB gzipped first-load on mobile.