The whereNull() method in collect.js is used to filter the values from a collection that is null.
Installation:
- In NodeJs:
npm install collect.js
- CDN for collect.js
<script src="https://cdnjs.com/libraries/collect.js"></script>
Syntax:
whereNull(key if any);
Parameters: It accepts the key of the object.
Returns: It returns the collection object.
Example 1:
Javascript
// Importing the collect.js module. const collect = require('collect.js'); let obj1 = [1, null, 3, null, 4, 5]; Â Â // Making a collection let collection = collect(obj1); Â Â // Filtering the null values; let collectionFilter = collection.whereNull(); console.log("Original collection is: ", collection) console.log("Filtered collection is: ", collectionFilter); |
Output:
Example 2: Using objects having null values.
Javascript
// Importing the collect.js module. const collect = require('collect.js'); let obj1 = [{ "a": null }, { "a": 1 },     { "b": null }, { "a": 3 }, { "a": null }];   // Making a collection let collection = collect(obj1);   // Filtering the null values; let collectionFilter = collection.whereNull("a");   // Printing the original collection console.log("Original collection is: ",         collection.all()) console.log("Filtered collection is: ",         collectionFilter.all()); |
Output:
Reference: https://collect.js.org/api/whereNull.html

