JavaScript

JavaScript standard: ECMA-262 (https://github.com/tc39/ecma262); a.k.a. ECMAScript.

New features: https://github.com/tc39/proposals/blob/master/finished-proposals.md

JavaScript Engines

Browser

• Chrome: V8
• Firefox: SpiderMonkey (the first JavaScript engine, originally used in Netscape Navigator) written in C++, Rust and JavaScript.
• Safari: Nitro

Server-side

• Node.js: uses the Google V8 JavaScript engine to execute code.
• Deno: the name is just node reordered. written in Rust.
• Bun: written in Zip and cpp; as name suggests, also a bundler.

Browser Object Model (BOM)

window object is used to interact with the browser. The following object can be used directly or under window, e.g. window.navigator or navigator

• document: HTML DOM
• navigator: to get browser information
• history
• screen
• location: url, host, path, protocol (NOT the user location)

JavaScript Ecosystem

Most popular web frameworks

• React: developed and used by Facebook
  • Next.js: built on top of React.js
• Angular: developed by Google
• Vue

Registries

• npm: the widely used registry, with millions of packages.
• jsr: the new regsitry, with native TypeScript support; ECMAScript modules only; built for all runtimes (node, deno, bun, browsers).

Bundler

• WebPack: for apps. Introduced the JavaScript world to the concept of a convention-over-configuration, all-in-one build-pipeline.
• Rollup: for libs.
• Vite: written in Go; the successor to Webpack?
• Turbopack: written in Rust; developed by Vercel; the sibling of Turborepo. Together, they make up the two cornerstones of Vercel’s systems-oriented efforts to evolve front-end tooling: Turbopack is the bundler and Turborepo is monorepo build tool.

Typecheck

• TypeScript: can be compiled to JavaScript
  • better tooling: advanced autocompletion, navigation, and refactoring
  • developed by Microsoft
  • SUPERSET OF JAVASCRIPT, javascript code is also valid typescript code
• Flow: also developed by Facebook, so works fine with React

Other notable libs

• Babel: the compiler
• D3 / HighCharts: for data visualization
• Express.js: the node.js web framework
• Bootstrap: the CSS framework from Twitter.
• Lerna: build multiple packages from the same repo.
• ESLint: lint...

es6 backtick

Template literals can be used multi line and may use "interpolation" to insert the content of variables:

var a = 123,
  str = `---
   a is: ${a}
----`;
console.log(str);

Will output:

---
   a is: 123
---

Integer

JavaScript does not have an integer type. JavaScript is only able to handle 52bit integers.

Modern js cheatsheet

https://github.com/mbeaudru/modern-js-cheatsheet