Move non-zeroes to the left of an array.

move-non-zero-array.js

const a = [2,3,0,0,0,0,0,2,3,4,0,2,0,3,0,1,8];


function leftify(arr) {
    let leftmost = 0;
    arr.forEach((el, idx) => {
      if(el !== 0) {
        const elements = arr.splice(idx,1);
        arr.splice(leftmost,0,...elements);
        leftmost++;
      }
    })
  return arr;
}


console.log(leftify(a));

function leftify_a(arr) {
  let left = 0;
  let tmp
  arr.forEach((value, idx) => {
    if(value !== 0) {
      tmp = arr[left];
      arr[left] = value;
      arr[idx] = tmp;
      left++;
    }
  });
  return arr;
}