Collect.js | collapse() Method Last Updated : 30 Jun, 2020 Comments Improve Suggest changes Like Article Like Report Collect.js is a fluent and convenient wrapper for working with arrays and objects. The JavaScript array is first transformed into a collection and then the function is applied to the collection. The collapse() method convert collection of arrays into a single flat array. Installation: Collect.js can be installed via NPM: npm install --save collect.js You can also use CDN of collect.js <script src="https://cdnjs.com/libraries/collect.js"></script> Syntax: collect(array).collapse() Parameters: The collect() takes one argument that is converted into the collection and then collapse() function is applied on it, which will convert into a single flat array. Return Value: Returns an array. Below examples illustrate the collapse() method in JavaScript: Example 1: Here collect = require('collect.js') is used to import the collect.js library into the file. javascript const collect = require('collect.js'); let arr = [1, [1, 2], [{}, 3]] // convert array into collection const collection = collect(arr); // collapsing the array into single array const collapased = collection.collapse(); // returning the array with all() method. let singleArray = collapased.all(); console.log("Single array: ", singleArray); Output Example 2: javascript const collect = require('collect.js'); let arr = [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10]] // convert array into collection const collection = collect(arr); // collapsing the array into single array const collapased = collection.collapse(); // returning the array with all() method. let singleArray = collapased.all(); console.log("Single array: ", singleArray); Output Comment More infoAdvertise with us Next Article Collect.js | combine() Method I iamsahil1910 Follow Improve Article Tags : JavaScript Web Technologies Collect.js Similar Reads Collect.js Collect.js is the javascript library for collecting data from tree-based structures. This library is used on JavaScript Array and Objects. Collect.js TutorialWhy Collect.js? It is a fluent and convenient wrapper for working with arrays and objects. It provides us with different functions that help i 1 min read Collect.js Introduction Collect.js is a JavaScript library for collecting data from tree-based structures. This library is used on JavaScript Array and Objects. Features: Some of the important features of Collect.js are: It is a fluent and convenient wrapper for working with arrays and objects.It provides us with different 2 min read Collect.js | all() Method The all() method is used to return the underlying array or object represented by the collection. The JavaScript array is first transformed into a collection and then the function is applied to the collection. Syntax: collect(array).all() Parameters: The method does not accept any parameter. Return 1 min read Collect.js average() Method The average() method is used to return the average of all the items in a collection. This method is an alias of avg() method. Syntax: collect(array).average() Parameters: The collect() method takes one argument that is converted into the collection and then average() function is applied on it, which 1 min read Collect.js | avg() Method Collect.js is a fluent and convenient wrapper for working with arrays and objects. The JavaScript array is first transformed into a collection and then the function is applied to the collection. The avg() method returns the average of all the items in a collection. Installation: Collect.js can be in 2 min read Collect.js | collapse() Method Collect.js is a fluent and convenient wrapper for working with arrays and objects. The JavaScript array is first transformed into a collection and then the function is applied to the collection. The collapse() method convert collection of arrays into a single flat array. Installation: Collect.js can 2 min read Collect.js | combine() Method Collect.js is a fluent and convenient wrapper for working with arrays and objects. The JavaScript array is first transformed into a collection and then the function is applied to the collection.The combine() method combines two different arrays with keys-values. Installation:  Collect.js can be in 1 min read Collect.js concat() Method The concat() method is used to return the merged arrays or objects represented by the collection. The JavaScript array is first transformed into a collection and then the function is applied to the collection. Syntax: collect(array1).concat(array2) Parameters: The collect() method takes one argument 2 min read Collect.js contains() Method The contains() method is used to determines whether the collection contains a given item or not. If it contains the item then it returns true otherwise false. The JavaScript array is first transformed into a collection and then the function is applied to the collection. Syntax:  collect(array).cont 2 min read Collect.js countBy() Method The countBy() method is used to count the occurrence of values in the collection. This method counts the occurrence of every element. Syntax: collect(array).countBy() Parameters: The collect() method takes one argument that is converted into the collection and then countBy() method is applied on it. 1 min read Like