How Can I Efficiently Move an Element Within a JavaScript Array?

Moving Elements Within an Array

In programming, it's often necessary to manipulate arrays by changing the positions of their elements. One common operation is moving an element from one array position to another.

The Challenge

Consider the following array:

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

The task is to write a function that allows you to move any element of the array to a specified index. For example, you may want to move 'd' to the left of 'b' or 'a' to the right of 'c'.

The Solution

Below is a JavaScript function that tackles this challenge:

function array_move(arr, old_index, new_index) {
    if (new_index >= arr.length) {
        var k = new_index - arr.length + 1;
        while (k--) {
            arr.push(undefined);
        }
    }
    arr.splice(new_index, 0, arr.splice(old_index, 1)[0]);
}

Usage

To move an element, simply call the array_move function with the following arguments:

• arr: The array you want to modify.
• old_index: The current index of the element you want to move.
• new_index: The desired index for the element after it has been moved.

For example, to move 'd' to the left of 'b', you would call:

array_move(array, 3, 1);

This would result in the following array:

['a', 'd', 'b', 'c', 'e']

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