Memoize function for various arguments

memoize.js

const memoize = function (func) {
  const hashCode = function (value) {
    var hash = 0,
      i,
      chr,
      len;

    try {
      value = JSON.stringify(value);
    } catch (e) {
      value = value.toString();
    }

    if (value.length === 0) {
      return hash;
    }

    for (i = 0, len = value.length; i < len; i++) {
      chr = value.charCodeAt(i);
      hash = (hash << 5) - hash + chr;
      hash |= 0; // Convert to 32bit integer
    }

    return hash;
  };

  let memo = new Map();

  return function () {
    // let key = Array.from(arguments).reduce(
    //   (accu, curr) => { console.log(curr, ": ", hashCode(curr)); return accu + "," + hashCode(curr);},
    //   ""
    // );
    let key = Array.from(arguments).map(
      (val) =>  hashCode(val)
    ).join(",");

    // return cached value if exists
    if (memo.has(key)) {
      return memo.get(key);
    }

    // call function
    let result = func.apply(this, arguments);

    // 
    memo.set(key, result);

    return result;
  };
};

/*
  // Examples
  let addObj = (o, p) => o.v + p.v;
  addObj = memoize(addObj);
  addObj({v: 2}, {v: 6});

  let addArr = (u, v) => u[0] + v[0];
  addArr = memoize(addArr);
  addArr([2], [6]);

  let add = (a, b) => a + b;
  add = memoize(add);
  add(2, 3);
 */