JavaScript weakMap.has() Method
Below is the example of weakMap.has() method.
- Example:
<script>functiongfg() {const weakmap =newWeakMap();const key = {};weakmap.set(key,'gfg');document.write(weakmap.has(key));}gfg();</script>chevron_rightfilter_none - Output:
true
The weakMap.has() is an inbuilt function in JavaScript which is used to return a boolean value which indicates whether an element with a particular key presents 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.
Example:
Input: weakmap1.has(key1) Output: true
JavaScripts to show the working of this function:
Code #1:
<script> // Creating a WeakMap() object const weakmap1 = new WeakMap(); // Creating a key "key1" const key1 = {}; // setting element 'gfg' to the key "key1" weakmap1.set(key1, 'gfg'); // Testing whether the key is present // in the weakMap() object or not document.write(weakmap1.has(key1)); </script> |
chevron_right
filter_none
Output:
true
Code #2:
<script> // Creating a WeakMap() object const weakmap1 = new WeakMap(); // Creating a key "key1" const key1 = {}; // Testing whether the key is present // in the weakMap() object or not document.write(weakmap1.has(key1)); </script> |
chevron_right
filter_none
Output:
false
Here output is false because the key “key1” has not been set at the end of the weakMap object.
Supported Browsers:
- Google Chrome
- Internet Explorer
- Firefox
- Apple Safari
- Opera
