How to Merge/Flatten an array of arrays in JavaScript ?
Merging or flattening an array of arrays in JavaScript involves combining multiple nested arrays into a single-level array. This process involves iterating through each nested array and appending its elements to a new array, resulting in a flattened structure.
We can Merge/Flatten an array of arrays in Javascript in the following ways:
Table of Content
- Using Array Flat() Method
- Using Spread Operator
- Using Underscore.js _.flatten() Function
Method 1: Using Array Flat() Method
We will create an array of arrays, and then use the flat() method to concatenate the sub-array elements.
Example:
let arr = [[1], [2, 3], [4], ["GFG"]];
console.log(arr.flat());
Output
[ 1, 2, 3, 4, 'GFG' ]
Method 2: Using Spread Operator
We can also merge or flatten an array of arrays using the concat() method and the Spread Operator.
Example:
const arr = [[1], [2, 3], [4], ["GFG"]];
const flattened = [].concat(...arr);
console.log(flattened);
Output
[ 1, 2, 3, 4, 'GFG' ]
Method 3: Using Underscore.js _.flatten() Function
The _.flatten() function is an inbuilt function in the Underscore.js library of JavaScript which is used to flatten an array that is nested to some level.
For installing Underscore.js, use the below command:
npm install underscore
const _ = require('underscore');
console.log(_.flatten([1, [2], [3, [4, [5, [6, [7]]]]]]));
Output:
[1, 2, 3, 4, 5, 6, 7]
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