Zapp and Beyond – JavaScript Framework Thoughts Part 1

Three years ago I was using Backbone and other similar frameworks for the first time… as an experiment I created Zapp, which was a super minimalistic variation on the idea of easy Object instantiation with inheritance, routers/deep linking and custom events. Here is the old repository:

https://github.com/ZevanRosser/Zapp

The source for Zapp is pretty short:

var Zapp = Zapp ||
function(a, b, c) {
  b = b || {};
  c = c || {};
  if (typeof a != "function") {
    b = a;
    a = Zapp._ctor;
  }
  if (typeof a == "function" && !b.prototype) {
    b.constructor = a;
    a.prototype = b;
    return a;
  } else if (typeof a == "function" && typeof b == "function") {
 
    b.prototype = new a();
    b.prototype.constructor = b;
 
    for (var i in c) {
      b.prototype[i] = c[i];
    }
    b.prototype.proto = a.prototype;
    b.prototype.sup = function() {
      a.apply(this, arguments);
    }
    return b;
  }
  return {};
};
 
Zapp.Object = Zapp;
 
Zapp._ctor = function() {};
 
Zapp.Events = function() {};
 
Zapp.Events.prototype = {
  constructor : Zapp.Events,
  _makeListeners: function() {
    this._listeners = this._listeners || [];
  },
  trigger: function(type, data) {
    this._makeListeners();
    var leng = this._listeners.length;
    for (var i = 0; i < leng; i++) {
      var listener = this._listeners[i];
      if (listener == undefined) continue;
      if (listener.type == type) {
        listener.callback.call(listener.ctx || this, data);
      }
    }
    return this;
  },
  on: function(type, callback, ctx) {
    this._makeListeners();
    this._listeners.push({
      type: type,
      callback: callback,
      ctx: ctx
    });
    return this;
  },
  off: function(type, callback) {
    this._makeListeners();
    for (var i = 0; i < this._listeners.length; i++) {
      var listener = this._listeners[i];
      if (listener == undefined) continue;
 
      if (listener.type == type && (listener.callback == callback || callback == undefined)) {
        this._listeners.splice(i, 1);
      }
    }
    return this;
  },
  allOff: function() {
    this._listeners = [];
    return this;
  }
};
 
// this code needs cleanup
//#path //exact match
//#path/name,name,name // values
//^path // regexp?
Zapp.Router = Zapp(Zapp.Events, function() {
  var self = this;
  if (Zapp.Router._instance) return Zapp.Router._instance;
  Zapp.Router._instance = self;
 
  var prevHash = "";
  var grabHash = /#(.*?)$/;
  var grabTrailingSlash = /\/$/;
 
  function getHash(){
    var hash = window.location.href.match(grabHash);
    return hash ? hash[1] : "";
  }
 
  if (getHash() == ""){
    setTimeout(function(){
      self.trigger("/");
      //self.trigger("change", {hash:"/"});
    }, 2);
 
  }else{
    setTimeout(checkHash, 2); 
  }
 
  function checkHash() {
    var hash = getHash();
    if (prevHash != hash) {
      if (hash == ""){
        self.trigger("/");
        return;
      }
      self.trigger("change", {hash:hash});
      for (var i = 0; i < self._listeners.length; i++) {
        var type = self._listeners[i].type;
        if (type == hash) {
 
          self.trigger(type);
          continue;
        }
        if (hash.match(new RegExp(type))) {
          self.trigger(type);
          continue;
        }
        var names = type.split(",");
        var startsWith = new RegExp("^" + names[0]);
        var starts = hash.match(startsWith);
        if (starts) {
 
          var values = hash.replace(startsWith, "");
 
          values = values.replace(grabTrailingSlash, "");
 
          values = values.substr(1).split("/");
 
          if (names.length - 1 == values.length) {
            var data = {};
 
            for (var j = 1; j < names.length; j++) {
 
              data[names[j]] = values[j - 1];
 
            }
            self.trigger(type, data);
 
          } else {
            continue;
          }
        }
 
      }
      prevHash = hash;
    }
  }
  setInterval(checkHash, 100);
 
}, {
  is: function() {
    this.on.apply(this, arguments);
    return this;
  },
  clear: function() {
    this.off.apply(this, arguments);
    return this;
  },
  clearAll: function() {
    this.allOff.apply(this, arguments);
    return this;
  }
});

The demos for Zapp give you an idea of how it works:

https://github.com/ZevanRosser/Zapp/tree/master/demos

Anyway, I’ve been heavily using Backbone along with Ractive (for templating) these days. And, well, it got me thinking of how I would like this stuff to work if I were to write my own framework. I know I may not use it if I write it, but just like Zapp, it could be interesting to think about again.

The first thing I was thinking about was how frameworks like Ractive and Backbone use get and set methods:

1
2
3

this.set('someValue', 100);
// or
this.get('someValue);

This enables events to occur when a value on a model or view changes so that a template can update or some other part of your program can update. I thought it would be cool to do something different…

This is really just a first though, but what if properties on an object literal were accompanied by a method that set them – of the same name prefixed by something like a $ or even set and then camel case the property:

// get a variable like normal:
var myName = obj.person.name;
//set it with the new method:
obj.person.$name('Zevan'); 
// now
obj.person.name = 'Zevan';

With some tweaking I was able to get a prototype of this functionality to work:

(function() {
 
  if (!Array.isArray) {
    Array.isArray = function(arg) {
      return Object.prototype.toString.call(arg) === '[object Array]';
    };
  }
 
  window.Watch = function(data) {
    this.data = this.process(data);
  };
 
  Watch.prototype = {
    constructor : Watch,
    process : function(obj, keyPath) {
      var path, temp, key;
      keyPath = keyPath ? keyPath + '.' : '';
 
      if(obj === null || typeof(obj) !== 'object') return obj;
 
      temp = obj.constructor(); 
 
      for(key in obj) {
        if(obj.hasOwnProperty(key)) {
          path = keyPath + key;
          temp[key] = this.process(obj[key], path);
          (function(key, path) {
            temp['$' + key] = function(val, silent) {
              temp[key] = val;
              // dispatch some event
              console.log('set', '"' + path + '"', '=', val);
            }; 
            if (Array.isArray(temp[key])){
              temp['$' + key].refresh = function() {
                // dispatch some event
                console.log('refresh collection', path);
              };
            }
          })(key, path);
        }
      }
 
      return temp;
    }
  };
})();

So the way this works is like so:

var obj = {
  x : 100, 
  y : 100,
  vect : {a : 1, b: 2, c : 3} 
};
 
var w = new Watch(obj);
 
console.log('"x" start value = ', w.data.x); 
 
w.data.$x(2);
 
console.log('"x" is now', w.data.x); 
 
console.log('original "x" is still', obj.x);
 
console.log('------Something Different------');
 
console.log('"vect.a" start value = ', w.data.x); 
 
w.data.vect.$a('I am a!');
 
console.log(w.data.vect.a);

Which will output:

"x" start value =  100 watch5.html:19
set "x" = 2 watch.js:31
"x" is now 2 watch5.html:23
original "x" is still 100 watch5.html:25
------Something Different------ watch5.html:27
"vect.a" start value =  2 watch5.html:29
set "vect.a" = I am a! watch.js:31
I am a!

So, that’s pretty interesting, and if you JSON.stringify() the object, all the functions get removed which is nice if you need to pass the new JSON off to the server or something.

This entry was posted on Tuesday, November 11th, 2014 and is filed under html, html5, javascript, jquery. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response or Trackback from your own site.

zReference

Zapp and Beyond – JavaScript Framework Thoughts Part 1

Search

Recent Posts

Categories

Archives