JavaScript and WebAssembly features

This section explains the latest new features in JavaScript, the programming language specified by ECMA-262 (ECMAScript) and ECMA-402 (the ECMAScript Internationalization API), and in WebAssembly (Wasm).

We aim to provide concise explanations of new language features with easy-to-understand code examples. For more in-depth documentation, please refer to the external links in each explainer.

  1. globalThis ECMAScript
  2. Weak references and finalizers ECMAScript
  3. Stable Array.prototype.sort ECMAScript ES2019
  4. Symbol.prototype.description ECMAScript ES2019
  5. Object.fromEntries ECMAScript ES2019
  6. Promise combinators ECMAScript
  7. Array.prototype.flat and Array.prototype.flatMap ECMAScript ES2019
  8. Numeric separators ECMAScript
  9. String.prototype.matchAll ECMAScript ES2020
  10. Intl.ListFormat Intl
  11. Public and private class fields ECMAScript
  12. Intl.RelativeTimeFormat Intl
  13. Well-formed JSON.stringify ECMAScript ES2019
  14. JavaScript modules ECMAScript ES2015
  15. BigInt: arbitrary-precision integers in JavaScript ECMAScript ES2020
  16. Dynamic import() ECMAScript ES2020
  17. Promise.prototype.finally ECMAScript ES2018
  18. Intl.PluralRules Intl
  19. Object rest and spread properties ECMAScript ES2018