src/model.js
function off(property, callback){
    listeners[property] = listeners[property].filter(function (listener) {
      return listener !== callback;
    });
  }
function off(property, callback){
    listeners[property] = listeners[property].filter(function (listener) {
      return listener !== callback;
    });
  }
function off ( property , callback ) { listeners [ property ] = listeners [ property ] . filter ( function ( listener ) { return listener !== callback ; } ) ; }
Removes a change listener added using `on`.
Removes a change listener added using on .