last-index-of.js

function lastIndexOf (array, value) {
  const length = array.length;
  let output = -1;
  for (var i = 0; i < length; i++) {
    if (array[i] == value) {
      output = i;
    }
  }
  return output;
}

console.log(lastIndexOf([ 0, 1, 4, 1, 2 ], 1), "=?", 3);
console.log(lastIndexOf([ 0, 1, 4, 1, 2 ], 2), "=?", 4);
console.log(lastIndexOf([ 0, 1, 4, 1, 2 ], 3), "=?", -1);
console.log(lastIndexOf([ 5, 5, 5 ], 5), "=?", 2);
console.log(lastIndexOf([], 3), "=?", -1);