RealTime.js - update system for building ajax stuff like autocompletes

RealTime.js

/**
  * RealTime.js : Update system
  * Manage input (or textarea) smart callback on change
  * @author Gaetan Renaudeau <[email protected]>, Namolovan Nicolae <[email protected]>
  */
var RealTime = function(node, o) {
  var self = this;
  this.input = node;
  
  var getTime = function() {
    return new Date().getTime();
  }
  
  self.callback = o['update'] || function(){};
  self.textChange = o['textChange'] || function(){};
  self.timer = false;
  self.lastCall = getTime();
  self.lastSearch = self.input.value;
  self.minInterval = o['minInterval'] || 800; // min interval between each call to minimize requests
  self.maxInterval = o['maxInterval'] || 800; // max interval, to allow some updates
  self.minTextLength = o['minTextLength'] || 0;
  
  if (self.minInterval > self.maxInterval) self.maxInterval = self.minInterval + 100;
  
  // first couch
  this.onKeyup = function(e) {
    if (self.timer === false) {
        self.lastCall = getTime();
        self.timerStarted = getTime();
        self.ignoredKeys = 0;
        self.onInputChange();
    } 
    else {
      if ( /* maxInterval */ (getTime() - self.timerStarted) > self.maxInterval ) {
        clearTimeout(self.timer); // Don't need the timer anymore
        self.timer = false;
        self.lastCall = self.timerStarted; // Force to execute the update code
        self.onInputChange();
      }
      else {
        self.lastCall = getTime();
      }
    }
  }
  
  // second couch
  self.onInputChange = function() {
    var now = getTime();
    var newInputValue = self.input.value;
    var inputValue = self.lastSearch;
    if(/* text has changed */ inputValue!=newInputValue
    && /* enough letters to update */ (newInputValue.length==0 || newInputValue.length>=self.minTextLength) ) {
      self.textChange(inputValue);
      if(now-self.lastCall>self.minInterval) { /* min interval elapsed */
        /// UPDATE
        inputValue = newInputValue;
        self.lastSearch = inputValue;
        self.callback(inputValue, self.input);
        self.lastCall = getTime();
        self.timer = false;
      }
      else {
        self.timer = setTimeout(self.onInputChange, self.minInterval-(now-self.lastCall)+10);
      }
    }
  };
  
  self.input.addEventListener('keyup', self.onKeyup, false);
}