JavaScript Reflect has() Method
Last Updated :
30 May, 2023
JavaScript Reflect.has() method in JavaScript is used to check whether the property exists in an object or not. It works like the in operator as a function.
Syntax:
Reflect.has(target, propertyKey)
Parameters: This method accepts two parameters as mentioned above and described below:
- target: This parameter is the target object and it looks for the property.
- propertyKey: This parameter is the name of the property to be checked.
Return value: This method returns a Boolean value which indicates if the target has the property.
Exceptions: A TypeError is an exception given as the result when the target is not an object.
The below examples illustrate the Reflect.has() method in JavaScript:
Example 1: In this example, we will check if the object has the property or not using the Reflect.has() method in JavaScript.
javascript
const object1 = {
property1: 434
};
console.log(Reflect.has(object1, 'property1' ));
console.log(Reflect.has(object1, 'property2' ));
console.log(Reflect.has(object1, 'toString' ));
let x = { foo: 1 };
console.log(Reflect.has(x, 'foo' ));
console.log( 'foo' in x);
console.log(Reflect.has(x, 'bar' ));
console.log( 'bar' in x);
|
Output:
true
false
true
true
true
false
false
Example 2: In this example, we will check if the object has the property or not using the Reflect.has() method in JavaScript.
javascript
console.log(Reflect.has({ x: 0 }, 'toString' ));
let obj = new Proxy({}, {
has(t, k) { return k.startsWith( 'geeks' ) }
});
console.log(Reflect.has(obj, 'geeksforgeeks' ));
console.log(Reflect.has(obj, 'geekforgeek' ));
const val1 = { foo: 123 }
const val2 = { __proto__: val1 }
const val3 = { __proto__: val2 }
console.log(Reflect.has(val3, 'foo' ));
|
Output:
true
true
false
true
Supported Browsers: The browsers supported by JavaScript Reflect.has() Method are listed below:
- Google Chrome 49 and above
- Edge 12 and above
- Firefox 42 and above
- Opera 36 and above
- Safari 10 and above
We have a complete list of Javascript Reflects methods, to check those go through the JavaScript Reflect Reference article.
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