gistfile1.js

“Here is a simplified implementation, though there are plenty of more robust versions available.

var memoize = function(f) {
  var cache = {};

  return function() {
    var arg_str = JSON.stringify(arguments);
    cache[arg_str] = cache[arg_str] || f.apply(f, arguments);
    return cache[arg_str];
  };
};
Something to note is that you can transform some impure functions into pure ones by delaying evaluation:

var pureHttpCall = memoize(function(url, params){
  return function() { return $.getJSON(url, params); }
});”

Excerpt From: drboolean. “mostly-adequate-guide.” iBooks. https://itunes.apple.com/WebObjects/MZStore.woa/wa/viewBook?id=828C74EE750961AEB99EE55C5B4B538A