This is an AjaxSpinner component, written for the React framework using EventEmitter2

AjaxSpinner.js

/** @jsx React.DOM */
define(['react'], function(React){

  /**
   * Ajax Spinner
   *
   * Props:
   *  - {object} data
   *    - {String} data.imgSrc
   *    - {int} data.width
   *    - {int} data.height
   *    - {String} data.alt
   *  - {EventEmitter2} eventEmitter
   *
   * @type {Function}
   */
  var AjaxSpinner = React.createClass({

    getInitialState: function() {
      return {style: {display: 'none'}};
    },

    componentDidMount: function() {
      var that = this, p = this.props, ee = p.eventEmitter;
      ee.on(p.startEvent, function(){
        that.setState({style: {display:'block'}});
      });
      ee.on(p.endEvent, function(){
        that.setState({style: {display:'none'}});
      });
    },

    render: function() {
      var style = this.state.style;
      return (
        <img style={style} src={this.props.data.imgSrc} width={this.props.data.width} height={this.props.data.height} alt={this.props.data.alt}/>
        );
    }
  });

  return AjaxSpinner;
});