Collect.js is a fluent and convenient wrapper for working with arrays and objects. The unlessNotEmpty() function executes the callback function when the collection is empty.
Installation: Install the Collect.js module using the following command:
npm install --save collect.js
Syntax:
collection.unlessNotEmpty(callback)
Parameters: This function takes only one parameter i.e. the callback function which executes if the collection is empty.
Return Value: This function returns the new collection object.
Example 1: Filename-index.js
Javascript
// Requiring module const collect = require( 'collect.js' ) // User defined collection var myCollection = [] // Creating collection object const collection = collect(myCollection); // Callback execution since collection object is empty collection.unlessNotEmpty(item => item.push(1)); // Printing collection console.log(collection.all()); |
Run the index.js file using the following command:
node index.js
Output:
[ 1 ]
Example 2: Filename-index.js
Javascript
// Requiring module const collect = require( 'collect.js' ) // User defined collection var myCollection = [1, 2, 3] // Creating collection object const collection = collect(myCollection); // No callback execution since // collection is not empty collection.unlessNotEmpty((item) => { item.push(4) item.push(5) }); // Printing collection console.log(collection.all()); |
Run the index.js file using the following command:
node index.js
Output:
[ 1, 2, 3]
Reference: https://collect.js.org/api/unlessNotEmpty.html