JavaScript – Flatten an Array

To flatten an Array in JavaScript, call flat() method on this array. flat() method returns a new array with the contents of the original array flattened to a one-dimensional array.

Examples

In the following script, we take a two dimensional array arr, and flatter it using Array.flat() method.

index.html

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<!DOCTYPE html>
<html lang="en">
<body>
    <pre id="output"></pre>
    <script>
        var arr = [['apple', 'banana'], ['cherry', 'mango']];
        var result = arr.flat();
        document.getElementById('output').innerHTML = result;
    </script>
</body>
</html>

In the following script, we take a three-dimensional array arr, and flatter the array.

index.html

</>
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<!DOCTYPE html>
<html lang="en">
<body>
    <pre id="output"></pre>
    <script>
        var arr = [[[2, 1], [4, 8]], [[6, 0], [7, 9]]];
        var result = arr.flat();
        document.getElementById('output').innerHTML = result;
    </script>
</body>
</html>

Conclusion

In this JavaScript Tutorial, we have learnt how to use Array.flat() method to flatten a multi-dimensional array into a one-dimensional array with examples.