JavaScript copy array without reference

Use JSON.parse() and JSON.stringify() methods to copy the array without reference in JavaScript. If these objects are simple objects, they can be serialized in JSON.

JSON.parse(JSON.stringify(mainArray));

JavaScript copy array without reference

In simple example code using this method, we can create a copy of an array. Please check the below example.

<!DOCTYPE html>
<html>
<body>

  <script>
    let original = [1,2,3,4,5];
    let cloned = JSON.parse(JSON.stringify(original)); 

    original[0] = -1;
    console.log(cloned); 
    console.log(original);

  </script>

</body>
</html>

Output:

More examples 2d array

let original = [
  [1, 2],
  [3, 4]
];
let cloned = JSON.parse(JSON.stringify(original)); // copy everything from original 
original[0][0] = -1;

console.log(cloned); // the cloned array element value changes too
console.log(original);

Output:

[[1,2],[3,4]]
[[-1,2],[3,4]]

Copy array by value

Basically, the slice() operation clones the array and returns a reference to a new array. The slice() copies object references into the new array. Both the original and new arrays refer to the same object. If a referenced object changes, the changes are visible to both the new and original arrays.

let oldArray = [1, 2, 3, 4, 5];

let newArray = oldArray.slice();

console.log({newArray});

Output:{ "newArray": [ 1, 2, 3, 4, 5 ] }

Do comment if you have any doubts or suggestions on this Array topic.

Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.
OS: Windows 10
Code: HTML 5 Version

JavaScript copy array without reference | Example code