Lodash _.isWeakMap() Method

Lodash _.isWeakMap() method is used to find whether the given value is a weakmap object or not. It returns True if the given value is a weakmap object. Otherwise, it returns false.

Syntax:

_.isWeakMap(value);

Parameters:

• value: This parameter holds the value to check.

Return Value:

This method returns true if the value is a weakmap, else false.

Example 1: In this example, we are checking whether the given value is weakMap or not and printing the result in the console.

// Requiring the lodash library  
const _ = require('lodash');

// Creating a array of size 2
// using constructor 
let obj = new Array(2);

// Filling value 5 in the array 
obj.fill(5)

// Use of _.isWeakMap() method 
console.log(_.isWeakMap(obj)); 

Output:

false

Example 2: In this example, we are checking whether the given value is weakMap or not and printing the result in the console.

// Requiring the lodash library  
const _ = require('lodash');

// Use of _.isWeakMap() method 
// When a weak set is given
console.log(_.isWeakMap(new WeakMap));

// When a weak set is not given
console.log(_.isWeakMap(new Map));

Output:

true
false

Note: This will not work in normal JavaScript because it requires the library lodash to be installed.

Reference: https://lodash.com/docs/4.17.15#isWeakMap