Mixin for status observing - on records, record arrays etc.

observe_status.js

// ==========================================================================
// Project:   Billapp.ObserveStatus
// Copyright: ©2011 Blueberry.cz Apps s.r.o.
// ==========================================================================
/*globals Billapp */

/** @namespace

  @version 0.1
*/
Billapp.ObserveStatus = {

  //........................................................................
  // METHODS

  /**
    Observes record status and invokes callback when record reaches
    given status.

    @param {Number} status Desired status.
    @param {Object} target
    @param {Function|String} method

    @returns {SC.Object} reciever.
  */
  observeStatus: function(status, target, method) {
    var context = { status: status, target: target, method: method };
    // normalize method first
    if (SC.typeOf(method) === SC.T_STRING) method = target[method];
    this.addObserver('status', this, '_os_statusDidChange', context);
    return this;
  },

  //........................................................................
  // PRIVATE

  /** @private */
  _os_statusDidChange: function(target, key, value, context) {
    var recordStatus = target.get(key);
    if (recordStatus & context.status) {
      target.removeObserver(key, this, '_os_statusDidChange');
      if (context.method) context.method.call(context.target, this, key);
    }
  }

};