The Map[@@species]
accessor property returns the Map
constructor.
Description
The species accessor property returns the default constructor for Map
objects. Subclass constructors may over-ride it to change the constructor assignment.
Examples
Species in ordinary objects
The species property returns the default constructor function, which is the Map
constructor for Map
objects:
Map[Symbol.species]; // function Map()
Species in derived objects
In a derived collection object (e.g. your custom map MyMap
), the MyMap
species is the MyMap
constructor. However, you might want to overwrite this, in order to return parent Map
objects in your derived class methods:
class MyMap extends Map { // Overwrite MyMap species to the parent Map constructor static get [Symbol.species]() { return Map; } }
Specifications
Specification |
---|
ECMAScript (ECMA-262) The definition of 'get Map [ @@species ]' in that specification. |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
@@species | Chrome Full support 51 | Edge Full support 13 | Firefox Full support 41 | IE No support No | Opera Full support 38 | Safari Full support 10 | WebView Android Full support 51 | Chrome Android Full support 51 | Firefox Android Full support 41 | Opera Android Full support 41 | Safari iOS Full support 10 | Samsung Internet Android Full support 5.0 | nodejs
Full support
6.5.0
|
Legend
- Full support
- Full support
- No support
- No support
- User must explicitly enable this feature.
- User must explicitly enable this feature.