bloom-layout/example/node_modules/fbjs/lib/EventListener.js

layout components used in bloom packages

'use strict';

/**
 * Copyright (c) 2013-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @typechecks
 */

var emptyFunction = require('./emptyFunction');

/**
 * Upstream version of event listener. Does not take into account specific
 * nature of platform.
 */
var EventListener = {
  /**
   * Listen to DOM events during the bubble phase.
   *
   * @param {DOMEventTarget} target DOM element to register listener on.
   * @param {string} eventType Event type, e.g. 'click' or 'mouseover'.
   * @param {function} callback Callback function.
   * @return {object} Object with a `remove` method.
   */
  listen: function listen(target, eventType, callback) {
    if (target.addEventListener) {
      target.addEventListener(eventType, callback, false);
      return {
        remove: function remove() {
          target.removeEventListener(eventType, callback, false);
        }
      };
    } else if (target.attachEvent) {
      target.attachEvent('on' + eventType, callback);
      return {
        remove: function remove() {
          target.detachEvent('on' + eventType, callback);
        }
      };
    }
  },

  /**
   * Listen to DOM events during the capture phase.
   *
   * @param {DOMEventTarget} target DOM element to register listener on.
   * @param {string} eventType Event type, e.g. 'click' or 'mouseover'.
   * @param {function} callback Callback function.
   * @return {object} Object with a `remove` method.
   */
  capture: function capture(target, eventType, callback) {
    if (target.addEventListener) {
      target.addEventListener(eventType, callback, true);
      return {
        remove: function remove() {
          target.removeEventListener(eventType, callback, true);
        }
      };
    } else {
      if (process.env.NODE_ENV !== 'production') {
        console.error('Attempted to listen to events during the capture phase on a ' + 'browser that does not support the capture phase. Your application ' + 'will not receive some events.');
      }
      return {
        remove: emptyFunction
      };
    }
  },

  registerDefault: function registerDefault() {}
};

module.exports = EventListener;