59 lines
1.6 KiB
JavaScript
59 lines
1.6 KiB
JavaScript
/**
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @flow strict-local
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* @format
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*/
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'use strict';
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import Platform from '../Utilities/Platform';
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let isEnabled = false;
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if (Platform.OS === 'web') {
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const canUseDOM = Boolean(
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typeof window !== 'undefined' &&
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window.document &&
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window.document.createElement,
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);
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if (canUseDOM) {
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/**
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* Web browsers emulate mouse events (and hover states) after touch events.
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* This code infers when the currently-in-use modality supports hover
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* (including for multi-modality devices) and considers "hover" to be enabled
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* if a mouse movement occurs more than 1 second after the last touch event.
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* This threshold is long enough to account for longer delays between the
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* browser firing touch and mouse events on low-powered devices.
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*/
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const HOVER_THRESHOLD_MS = 1000;
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let lastTouchTimestamp = 0;
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const enableHover = () => {
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if (isEnabled || Date.now() - lastTouchTimestamp < HOVER_THRESHOLD_MS) {
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return;
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}
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isEnabled = true;
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};
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const disableHover = () => {
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lastTouchTimestamp = Date.now();
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if (isEnabled) {
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isEnabled = false;
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}
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};
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document.addEventListener('touchstart', disableHover, true);
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document.addEventListener('touchmove', disableHover, true);
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document.addEventListener('mousemove', enableHover, true);
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}
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}
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export function isHoverEnabled(): boolean {
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return isEnabled;
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}
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