The static Reflect
.defineProperty()
method is like Object.defineProperty()
but returns a Boolean
.
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Syntax
Reflect.defineProperty(target, propertyKey, attributes)
Parameters
target
- The target object on which to define the property.
propertyKey
- The name of the property to be defined or modified.
attributes
- The attributes for the property being defined or modified.
Return value
A Boolean
indicating whether or not the property was successfully defined.
Exceptions
A TypeError
, if target
is not an Object
.
Description
The Reflect.defineProperty
method allows precise addition to or modification of a property on an object. For more details, see the Object.defineProperty
which is similar.
One key difference: Object.defineProperty
returns the object or throws a TypeError
if the property has not been successfully defined. Reflect.defineProperty
, however, simply returns a Boolean
indicating whether or not the property was successfully defined.
Examples
Using Reflect.defineProperty()
let obj = {} Reflect.defineProperty(obj, 'x', {value: 7}) // true obj.x // 7
Checking if property definition has been successful
With Object.defineProperty
, which returns an object if successful, or throws a TypeError
otherwise, you would use a try...catch
block to catch any error that occurred while defining a property. ]
Because Reflect.defineProperty
returns a Boolean success status, you can just use an if...else
block here:
if (Reflect.defineProperty(target, property, attributes)) { // success } else { // failure }
Specifications
Specification |
---|
ECMAScript (ECMA-262) The definition of 'Reflect.defineProperty' in that specification. |
Browser compatibility
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
defineProperty | Chrome Full support 49 | Edge Full support 12 | Firefox Full support 42 | IE No support No | Opera Full support 36 | Safari Full support 10 | WebView Android Full support 49 | Chrome Android Full support 49 | Firefox Android Full support 42 | Opera Android Full support 36 | Safari iOS Full support 10 | Samsung Internet Android Full support 5.0 | nodejs Full support 6.0.0 |
Legend
- Full support
- Full support
- No support
- No support