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