The static Reflect
.has()
method works like the in
operator as a function.
Syntax
Reflect.has(target, propertyKey)
Parameters
target
- The target object in which to look for the property.
propertyKey
- The name of the property to check.
Return value
A Boolean
indicating whether or not the target has the property.
Exceptions
A TypeError
, if target
is not an Object
.
Description
The Reflect.has
method allows you to check if a property is in an object. It works like the in
operator as a function.
Examples
Using Reflect.has()
Reflect.has({x: 0}, 'x'); // true Reflect.has({x: 0}, 'y'); // false // returns true for properties in the prototype chain Reflect.has({x: 0}, 'toString'); // Proxy with .has() handler method obj = new Proxy({}, { has(t, k) { return k.startsWith('door'); } }); Reflect.has(obj, 'doorbell'); // true Reflect.has(obj, 'dormitory'); // false
Specifications
Specification | Status | Comment |
---|---|---|
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Reflect.has' in that specification. |
Standard | Initial definition. |
ECMAScript Latest Draft (ECMA-262) The definition of 'Reflect.has' in that specification. |
Living Standard |
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.
Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|---|
Basic support | 49 | 12 | 42 | No | 36 | 10 |
Feature | Android webview | Chrome for Android | Edge mobile | Firefox for Android | IE mobile | Opera Android | iOS Safari |
---|---|---|---|---|---|---|---|
Basic support | 49 | 49 | Yes | 42 | No | 36 | 10 |
See also
Document Tags and Contributors
Tags:
Contributors to this page:
fscholz,
denimX,
jameshkramer,
nmve,
kdex,
bsara,
eduardoboucas,
gingerik
Last updated by:
fscholz,