Memoize function

memoize_function.js

function memoize(func) {
  var memo = {};
  var slice = Array.prototype.slice;
  
  return function() {
    var args = slice.call(arguments);  // what if func(1,2,3) needs to be treated as the same as func(2,3,1)

    if (args in memo) {
      return memo[args]
    } else {
      return (memo[args] = func.apply(this, args);
    }
  }
}
              
/*
Reference
1. https://medium.freecodecamp.org/understanding-memoize-in-javascript-51d07d19430e
2. https://www.sitepoint.com/implementing-memoization-in-javascript/

Someone can also reference lodash memozie function as well
https://github.com/lodash/lodash/tree/4.1.2-npm-packages/lodash.memoize
*/