JavaScript handler.getOwnPropertyDescriptor() method in Javascript is a trap for the Object.getOwnPropertyDescriptor() method. A property cannot be reported as non-existent if it exists as a non-configurable own property of the target object.
Syntax:
const p = new Proxy(target, {
getOwnPropertyDescriptor: function(target, prop) {
}
});
Parameters: This method accepts two parameters as mentioned above and described below:
- Target: This parameter is the target object.
- Prop: This parameter is the name of the property whose description should be retrieved.
Return value: This method returns an object or undefined.
Below examples illustrate the handler.getOwnPropertyDescriptor() method in JavaScript:
Example 1: In this example, we will see the use of handler.getOwnPropertyDescriptor() method in JavaScript.
javascript
const monster1 = { num: 4};const handler1 = { getOwnPropertyDescriptor(target, prop) { console.log(`Type : ${prop}`); return { configurable: true, enumerable: true, value: 5 }; }};const proxy1 = new Proxy(monster1, handler1);console.log(Object.getOwnPropertyDescriptor(proxy1, 'num').value);console.log(Object.getOwnPropertyDescriptor(proxy1, 'bool').enumerable); |
Type : num 5 Type : bool true
Example 2: In this example, we will see the use of handler.getOwnPropertyDescriptor() method in JavaScript.
javascript
const p = new Proxy({ VAL: 20 }, { getOwnPropertyDescriptor: function (target, prop) { console.log('Property : ' + prop); return { configurable: true, enumerable: true, value: 10 }; }});console.log(Object.getOwnPropertyDescriptor(p, 'VAL').value);const obj = { a: 10 };Object.preventExtensions(obj);const pval = new Proxy(obj, { getOwnPropertyDescriptor: function (target, prop) { return undefined; }});console.log(Object.getOwnPropertyDescriptor(pval)); |
Property : VAL 10 undefined
Supported Browsers:
The browsers are supported by handler.getOwnPropertyDescriptor() method is listed below:
- Google Chrome 49 and above
- Edge 12 and above
- Firefox 18 and above
- Opera 36 and above
- Safari 10 and above
We have a complete list of Javascript Proxy/handler methods, to check those go through the Javascript Proxy/handler Reference article.
