33 lines
1.2 KiB
Plaintext
33 lines
1.2 KiB
Plaintext
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/**
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* Copyright (c) 2013-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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* @providesModule TouchEventUtils
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*/
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const TouchEventUtils = {
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/**
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* Utility function for common case of extracting out the primary touch from a
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* touch event.
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* - `touchEnd` events usually do not have the `touches` property.
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* http://stackoverflow.com/questions/3666929/
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* mobile-sarai-touchend-event-not-firing-when-last-touch-is-removed
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*
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* @param {Event} nativeEvent Native event that may or may not be a touch.
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* @return {TouchesObject?} an object with pageX and pageY or null.
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*/
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extractSingleTouch: function (nativeEvent) {
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const touches = nativeEvent.touches;
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const changedTouches = nativeEvent.changedTouches;
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const hasTouches = touches && touches.length > 0;
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const hasChangedTouches = changedTouches && changedTouches.length > 0;
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return !hasTouches && hasChangedTouches ? changedTouches[0] : hasTouches ? touches[0] : nativeEvent;
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}
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};
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module.exports = TouchEventUtils;
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