The static Reflect.has() method works like the in operator as a function.
Reflect.has()
Try it
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
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
Reflect.has returns true for any inherited properties, like the in operator:
const a = {foo: 123} const b = {__proto__: a} const c = {__proto__: b} // The prototype chain is: c -> b -> a Reflect.has(c, 'foo') // true
Specifications
| Specification |
|---|
| ECMAScript Language Specification # sec-reflect.has |
Browser compatibility
| Desktop | Mobile | Server | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | Deno | Node.js | |
has |
49
|
12
|
42
|
No
|
36
|
10
|
49
|
49
|
42
|
36
|
10
|
5.0
|
1.0
|
6.0.0
|
See also
© 2005–2022 MDN 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
