babel/doc/caveats.md
2014-11-24 00:35:39 +11:00

2.3 KiB

Caveats

In order for certain features to work they require certain polyfills. You can satisfy all 6to5 feature requirements by using the included polyfill. You may alternatively selectively include what you need:

Feature Requirements
Abstract References experimental, Symbol
Array destructuring Array.isArray, Array.from
Async functions, Generators experimental, regenerator runtime
Comprehensions experimental, Array.isArray, Array.from
For Of Symbol, prototype[Symbol.iterator]
Object spread/rest experimental, Object.assign
Spread Array.isArray, Array.from

Classes

Built-in classes such as Date, Array and DOM cannot be subclassed due to limitations in ES5 implementations.

If you're inheriting from a class then static properties are inherited from it via __proto__, this is widely supported but you may run into problems with much older browsers.

NOTE: __proto__ is not supported on IE <= 9 so static properties will not be inherited. A possible workaround is to use super();:

class Foo {
  static foo() {

  }
}

class Bar extends Foo {
  static foo() {
    super();
  }
}