The static Reflect.set()
method works like setting a property on an object.
The static Reflect.set()
method works like setting a property on an object.
Reflect.set(target, propertyKey, value) Reflect.set(target, propertyKey, value, receiver)
target
The target object on which to set the property.
propertyKey
The name of the property to set.
value
The value to set.
receiver
Optional
The value of this
provided for the call to the setter for propertyKey
on target
. If provided and target
does not have a setter for propertyKey
, the property will be set on receiver
instead.
A Boolean
indicating whether or not setting the property was successful.
The Reflect.set
method allows you to set a property on an object. It does property assignment and is like the property accessor syntax as a function.
// Object let obj = {} Reflect.set(obj, 'prop', 'value') // true obj.prop // "value" // Array let arr = ['duck', 'duck', 'duck'] Reflect.set(arr, 2, 'goose') // true arr[2] // "goose" // It can truncate an array. Reflect.set(arr, 'length', 1) // true arr // ["duck"] // With just one argument, propertyKey and value are "undefined". let obj = {} Reflect.set(obj) // true Reflect.getOwnPropertyDescriptor(obj, 'undefined') // { value: undefined, writable: true, enumerable: true, configurable: true }
When the target
and receiver
are different, Reflect.set
will use the property descriptor of target
(to find the setter or determine if the property is writable), but set the property on receiver
.
const target = {}; const receiver = {}; Reflect.set(target, "a", 2, receiver); // true // target is {}; receiver is { a: 2 } const target = { a: 1 }; const receiver = {}; Reflect.set(target, "a", 2, receiver); // true // target is { a: 1 }; receiver is { a: 2 } const target = { set a(v) { this.b = v; } }; const receiver = {}; Reflect.set(target, "a", 2, receiver); // true // target is { a: [Setter] }; receiver is { b: 2 }
Specification |
---|
ECMAScript Language Specification # sec-reflect.set |
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 | |
set |
49 |
12 |
42 |
No |
36 |
10 |
49 |
49 |
42 |
36 |
10 |
5.0 |
1.0 |
6.0.0 |
© 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/set