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

Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Reflect.has' in that specification.
Standard Initial definition.
ECMAScript 2017 Draft (ECMA-262)
The definition of 'Reflect.has' in that specification.
Draft  

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 49 42 (42) No support No support No support
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support No support 42.0 (42) No support No support No support

See also

Document Tags and Contributors

 Contributors to this page: eduardoboucas, gingerik, fscholz
 Last updated by: eduardoboucas,