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:
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:
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]