How to convert a multidimensional array into a single array

Published July 28, 2020

To convert a multidimensional or nested array into a single array or flatten the array we can use the flat() method available in the array.

Suppose you have a nested array like this,

// nested array
let arr = ["John Doe", ["Lily Rose", 23]];

Let's convert this array into a single array using the flat() method available in the array.

// nested array
let arr = ["John Doe", ["Lily Rose", 23]];

// convert nested array into single array
let convertedArr = arr.flat();

console.log(convertedArr); // ["John Doe", "Lily Rose", 23]

By default, arr.flat() method only converts nested arrays up to 1 level deep.

What if we have nested arrays which are 3 levels deep like this,

// nested array with 3 levels
let arr = ["John Doe", ["Lily Rose", ["salary", ["baseSalary", 23000]]]];

For this to convert into a single array we can pass the depth to which we want to convert the array as an argument to the flat() method.

// nested array with 3 levels
let arr = ["John Doe", ["Lily Rose", ["salary", ["baseSalary", 23000]]]];

// converted nested array into single array which is 3 levels deep
let convertedArr = arr.flat(3);

console.log(convertedArr); // ["John Doe", "Lily Rose", "salary", "baseSalary", 23000]

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