OOP Events

gistfile1.js

// Here's the code I'm working with now:

Careplane = function() {};
Careplane.prototype.onPageLoad = function(ev) {
  if(this.firstRun)
    this.firstRun();

  this.doc = ev.originalTarget;
  this.chooseAndLoadDriver();
};

// Firefox extension loading code
Overlay = {
  onLoad: function() {
    var node = document.getElementById('somenode');
    if(node) {
      var extension = new Careplane();
      node.addEventListener("DOMContentLoaded", Util.proxy(extension.onPageLoad, extension), true);
    }
  }
}




// Contrast with

Careplane = function() {};
Careplane.prototype.welcome = function() { ... };
Careplane.prototype.chooseAndLoadDriver = function(doc) { ... };

ExtensionLoader = {
  onPageLoad: function(extension) {
    return function(ev) {
      extension.welcome();
      extension.chooseAndLoadDriver(ev.originalTarget);
    };
  }
}

// Firefox extension loading code
Overlay = {
  onLoad: function() {
    var node = document.getElementById('somenode');
    if(node) {
      var extension = new Careplane();
      node.addEventListener("DOMContentLoaded", ExtensionLoader.onPageLoad(extension), true);
    }
  }
}


// I think this more clearly defines an interface between Firefox's loading code and Careplane.
// The handler defined in ExtensionLoader uses a "tell, don't ask" policy (http://pragprog.com/articles/tell-dont-ask).
// It seems simpler overall and easier to read.
// It's a more functional approach using closures.
// It delegates the job of handling events into a separate class.