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Reflect.has

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

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
Basic support 49 12 42 No 36 10
Mobile
Android webview Chrome for Android Edge Mobile Firefox for Android Opera for Android iOS Safari Samsung Internet
Basic support 49 49 Yes 42 36 10 5.0
Server
Node.js
Basic support 6.0.0

See also

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/has