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How to Merge and Deduplicate Arrays in JavaScript

Learn two ways to merge and deduplicate two or more arrays using Javascript ES5 and ES6.

Authors
  • avatar
    Name
    Mike Tsamis
    Twitter

Using ES5 and ES6, this tutorial will explain how to merge two or more arrays into a single array containing only the unique values from each array.

ES5 Solution

Simply use the concat() method to merge two or more arrays. Note that this method will return a new array.

const arrayA = [1, 2, 3];
const arrayB = [4, 5, 6];

const arrayC = arrayA.concat(arrayB)

console.log(arrayC);
// expected output: Array [1, 2, 3, 4, 5, 6]

ES6 Solution

You can use the destructuring assignment syntax to unpack values from arrays, or properties from objects, into distinct variables.

const arrayA = [1, 2, 3];
const arrayB = [4, 5, 6];

const arrayC = [...arrayA, ...arrayB]

console.log(arrayC);
// expected output: Array [1, 2, 3, 4, 5, 6]

TL;DR

const arrayC = arrayA.concat(arrayB)

OR

const arrayC = [...arrayA, ...arrayB]

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