JavaScript weakMap has() Method
The Javascript weakMap.has() is an inbuilt function in JavaScript that is used to return a boolean value which indicates whether an element with a particular key is present in the weakmap object or not.
Syntax:
weakMap.has(key);
Parameters: It accepts a parameter ‘key’ which is the key of the element which is going to be tested for presence in the object weakmap.
Return values: It returns true if the element with the specified key is present in the weakmap object otherwise it returns false.
Below are examples of weakMap.has() method.
Example 1: Below is a basic example of weakmap.has() method that returns true.
javascript
function gfg() { const weakmap = new WeakMap(); const key = {}; weakmap.set(key, 'gfg'); console.log(weakmap.has(key));}gfg(); |
true
Example 2: Here the output is false because the key “key1” has not been set at the end of the weakMap object.
javascript
// Creating a WeakMap() objectconst weakmap1 = new WeakMap();// Creating a key "key1"const key1 = {};// Testing whether the key is present// in the weakMap() object or notconsole.log(weakmap1.has(key1)); |
false
We have a complete list of Javascript WeakMap methods, to check those please go through Javascript WeakMap Complete reference article.
Supported Browsers:
- Google Chrome 36 and above
- Edge 12 and above
- Firefox 6 and above
- Internet Explorer 11 and above
- Opera 23 and above
- Safari 8 and above
