copyWithin()

The copyWithin() method copies a sequence of elements within an array and pastes them at a specified position in-place, modifying the original array.

Example

const arr: number[] = [ 1, 2, 3, 4, 5 ];
arr.copyWithin( 2, 0, 2 );

console.log( arr ); // Output: [1, 2, 1, 2, 5]

• The first argument (2) is the target index where the copied elements will be placed.

• The second argument (0) is the start index of the elements to be copied.

• The third argument (2) is the exclusive end index of the copied elements.

This modifies arr to [1, 2, 1, 2, 5] by copying elements 1 and 2 and placing them at index 2, replacing the original values.