Slides from JSConf / phpied.com

Slides from JSConf / phpied.com

High Performance Kick Ass Web Apps (JavaScript edition)

View more Microsoft Word documents from Stoyan Stefanov.

Cleanup after yourself
property you no longer need

var myApp = {
   prop: huge
};
delete myApp.prop

DOM elements you no longer need

var el = $('mydiv');
el.parentNode.removeChild(el);

instead of ...

function myEvent(el, type, fn) {
   if (window.addEventListener) {
      el.addEventListener(type, fn, false);
   } else if (window.attachEvent) {
      el.attachEvent('on'+type, fn);
   } else {..}
}

Do ...

if (window.addEventListener) {
   var myEvent = function (el, type, fn) {
      el.addEventListener(type, fn, false);
} else if (window.attachEvent) {
      var myEvent = function (el, type, fn) {
         el.attachEvent('on' + type, fn);
      }
   }
}

Memoization

function myFunc (param) {
   if (!myFunc.cache) {
      myFunc.cache = {};
   }
   if (!myFunc.cache[param]) {
      var result = {}; // ...
      myFunc.cache[param] = result;
   }
   return myFunc.cache[param];
}