Collect.js unless() Method

The unless() method is executes the callback provided when false is evaluated by the first argument given to the method. 

Syntax:

collect.unless()

Parameters: The collect() method takes one argument that is converted into the collection and then unless() method is applied on it.

Return Value:  This method returns the merged collection elements.

Below example illustrate the unless() method in collect.js:

Example 1:

Javascript

const collect = require('collect.js');

let arr = ['C++', 'java', 'python'];

const collection = collect(arr);

collection.unless(false, items => items.push('c#'));

let newObject =  collection.all();

console.log(newObject);

Output:

["C++", "java", "python", "c#"]

Example 2:

Javascript

const collect = require('collect.js');

let arr = [1, 2, 3, 4];

const collection = collect(arr);

collection.unless(false,
    items => items.push(5, 6, 7));

let newObject =  collection.all();

console.log(newObject);

Output:

[1, 2, 3, 4, 5, 6, 7]