Collect.js is a fluent and convenient wrapper for working with arrays and objects. The whenEmpty() 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.whenEmpty(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
// 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.whenEmpty(item => item.push('Greetings'));
// Printing collection
console.log(collection.all());
Run the index.js file using the following command:
node index.js
Output:
[ 'Greetings' ]
Example 2: Filename-index.js
// Requiring module
const collect = require('collect.js')
// User defined collection
var myCollection = ['One', 'Two', 'Three']
// Creating collection object
const collection = collect(myCollection);
// No callback execution since collection is not empty
collection.whenEmpty((item) => {
item.push('Four')
item.push('Five')
item.push('Six')
});
// Printing collection
console.log(collection.all());
Run the index.js file using the following command:
node index.js
Output:
[ 'One', 'Two', 'Three']
Reference: https://collect.js.org/api/whenempty