How to duplicate elements in a js array?

Question

Whats the easiest way (with \"native\" javascript) to duplicate every element in a javascript array?

The order matters.

For example:

Answer 1

I came across this issue in my application, so I created this function:

function duplicateElements(array, times) {
  return array.reduce((res, current) => {
      return res.concat(Array(times).fill(current));
  }, []);
}

To use it, simple pass the array, and the number of times you want the elements to be duplicated:

duplicateElements([2, 3, 1, 4], 2);
// returns: [2, 2, 3, 3, 1, 1, 4, 4]