reduce.js

// write reduce without Array.reduce

// @param {Array} list
// @param {Function} fn takes (acc, result)
// @acc {*} acc is the starting point or working accumulator
const reduce (list, fn, acc) => {
  let i = 0;
  var len = list.length;
  while(i < len) {
    acc = fn(acc, list[i])
  }
  return acc;
}