blob: b5a73ba63c954f19c9270f262d98aa7b25a40026 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
|
/**
* Copyright (c) 2013-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
* @providesModule TouchEventUtils
*/
const 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) {
const touches = nativeEvent.touches;
const changedTouches = nativeEvent.changedTouches;
const hasTouches = touches && touches.length > 0;
const hasChangedTouches = changedTouches && changedTouches.length > 0;
return !hasTouches && hasChangedTouches ? changedTouches[0] : hasTouches ? touches[0] : nativeEvent;
}
};
module.exports = TouchEventUtils;
|
