d2-ui
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JavaScript
/**
* Copyright 2013-2014 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* @providesModule TouchEventUtils
*/
var TouchEventUtils = {
/**
* Utility function for common case of extracting out the primary touch from a
* touch event.
* - `touchEnd` events usually do not have the `touches` property.
* http://stackoverflow.com/questions/3666929/
* mobile-sarai-touchend-event-not-firing-when-last-touch-is-removed
*
* @param {Event} nativeEvent Native event that may or may not be a touch.
* @return {TouchesObject?} an object with pageX and pageY or null.
*/
extractSingleTouch: function(nativeEvent) {
var touches = nativeEvent.touches;
var changedTouches = nativeEvent.changedTouches;
var hasTouches = touches && touches.length > 0;
var hasChangedTouches = changedTouches && changedTouches.length > 0;
return !hasTouches && hasChangedTouches ? changedTouches[0] :
hasTouches ? touches[0] :
nativeEvent;
}
};
module.exports = TouchEventUtils;