Loader is base trait and it provides set of core properties and associated validations. Trait is useful for all the compositions providing high level APIs for creating JavaScript contexts that can access web content.

Loader is composed from the EventEmitter trait, therefore instances of Loader and their descendants expose all the public properties exposed by EventEmitter along with additional public properties:

Value changes on all of the above mentioned properties emit propertyChange events on an instances.

Example:

The following code creates a wrapper on hidden frame that reloads a web page in frame every time contentURL property is changed:

var hiddenFrames = require("hidden-frame");
var { Loader } = require("content");
var PageLoader = Loader.compose({
  constructor: function PageLoader(options) {
    options = options || {};
    if (options.contentURL)
      this.contentURL = options.contentURL;
    this.on('propertyChange', this._onChange = this._onChange.bind(this));
    let self = this;
    hiddenFrames.add(hiddenFrames.HiddenFrame({
      onReady: function onReady() {
        let frame = self._frame = this.element;
        self._emit('propertyChange', { contentURL: self.contentURL });
      }
    }));
  },
  _onChange: function _onChange(e) {
    if ('contentURL' in e)
      this._frame.setAttribute('src', this._contentURL);
  }
});