JavaScript - copy two dimensional array

In this article, we would like to show you how to create a copy of a two-dimensional array in JavaScript.

1. Using slice() with map() method

In this example, we use slice() method inside map() to copy all elements from the original array.

// ONLINE-RUNNER:browser;

const array = [
    ['a', 'b'],
    ['c', 'd']
];

const copy = array.map((item) => item.slice());

console.log(JSON.stringify(copy)); // [ [ 'a', 'b' ], [ 'c', 'd' ] ]

2. Using slice() with for loop

In this example, we use slice() method inside a for loop to iterate through the array and copy all of its elements.

// ONLINE-RUNNER:browser;

var array = [
    ['a', 'b'],
    ['c', 'd']
];

var copy = [];

for (var i = 0; i < array.length; i++) {
    copy[i] = array[i].slice();
}

console.log(JSON.stringify(copy)); // [ [ 'a', 'b' ], [ 'c', 'd' ] ]

See also

1. JavaScript - copy multi-dimensional array

References

1. Array.prototype.slice() - JavaScript | MDN