Observer JS

Observer

function ObserverList(){
  this.observerList = [];
}
 
ObserverList.prototype.add = function( obj ){
  return this.observerList.push( obj );
};

ObserverList.prototype.pull = function(obj){
 return this.observerList.slice(0,1);
}
 
ObserverList.prototype.count = function(){
  return this.observerList.length;
};
 
ObserverList.prototype.get = function( index ){
  if( index > -1 && index < this.observerList.length ){
    return this.observerList[ index ];
  }
};
 
ObserverList.prototype.indexOf = function( obj, startIndex ){
  var i = startIndex;
 
  while( i < this.observerList.length ){
    if( this.observerList[i] === obj ){
      return i;
    }
    i++;
  }
 
  return -1;
};
 
ObserverList.prototype.removeAt = function( index ){
  this.observerList.splice( index, 1 );
};