ECMAScript 2015 (ES6)

- OTHER

Support for the ECMAScript 2015 specification. Features include Promises, Modules, Classes, Template Literals, Arrow Functions, Let and Const, Default Parameters, Generators, Destructuring Assignment, Rest & Spread, Map/Set & WeakMap/WeakSet and many more.

IE

  1. 5.5 - 10: Not supported
  2. 11: Partial support

Edge

  1. 12 - 14: Partial support
  2. 15 - 18: Supported
  3. 79 - 85: Supported
  4. 86: Supported

Firefox

  1. 2 - 5: Not supported
  2. 6 - 53: Partial support
  3. 54 - 80: Supported
  4. 81: Supported
  5. 82 - 83: Supported

Chrome

  1. 4 - 20: Not supported
  2. 21 - 50: Partial support
  3. 51 - 85: Supported
  4. 86: Supported
  5. 87 - 89: Supported

Safari

  1. 3.1 - 7: Not supported
  2. 7.1 - 9.1: Partial support
  3. 10 - 13.1: Supported
  4. 14: Supported
  5. TP: Supported

Opera

  1. 9 - 12.1: Not supported
  2. 15 - 37: Partial support
  3. 38 - 70: Supported
  4. 71: Supported

iOS Safari

  1. 3.2 - 6.1: Not supported
  2. 7 - 9.3: Partial support
  3. 10 - 13.7: Supported
  4. 14: Supported

Opera Mini

  1. all: Not supported

Android Browser

  1. 2.1 - 4.3: Not supported
  2. 4.4 - 4.4.4: Partial support
  3. 81: Supported

Blackberry Browser

  1. 7: Not supported
  2. 10: Partial support

Opera Mobile

  1. 10 - 12.1: Not supported
  2. 59: Supported

Chrome for Android

  1. 85: Supported

Firefox for Android

  1. 79: Supported

IE Mobile

  1. 10: Not supported
  2. 11: Partial support

UC Browser for Android

  1. 12.12: Supported

Samsung Internet

  1. 4: Partial support
  2. 5 - 11.2: Supported
  3. 12.0: Supported

QQ Browser

  1. 10.4: Supported

Baidu Browser

  1. 7.12: Partial support

KaiOS Browser

  1. 2.5: Partial support

As ES6 refers to a huge specification and browsers have various levels of support, "Supported" means at least 95% of the spec is supported. "Partial support" refers to at least 10% of the spec being supported. For full details see the Kangax ES6 support table.

Resources:
ES6 New features: overview and comparisons
Exploring ES6 (book)
Polyfill for all possible ES2015 features is available in the core-js library
Sub-features:
Typed Arrays
let
Arrow functions
Rest parameters
ES6 Number
Proxy object
ES6 Template Literals (Template Strings)
ES6 classes
ES6 Generators
String.prototype.includes