31 lines
1.2 KiB
Markdown
31 lines
1.2 KiB
Markdown
### onUserInputChange
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Run the callback whenever the user input type changes (`mouse` or `touch`). Useful for enabling/disabling code depending on the input device. This process is dynamic and works with hybrid devices (e.g. touchscreen laptops).
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Use two event listeners. Assume `mouse` input initially and bind a `touchstart` event listener to the document.
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On `touchstart`, add a `mousemove` event listener to listen for two consecutive `mousemove` events firing within 20ms, using `performance.now()`.
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Run the callback with the input type as an argument in either of these situations.
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```js
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const onUserInputChange = callback => {
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let type = 'mouse',
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lastTime = 0;
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const mousemoveHandler = () => {
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const now = performance.now();
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if (now - lastTime < 20)
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(type = 'mouse'), callback(type), document.removeEventListener('mousemove', mousemoveHandler);
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lastTime = now;
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};
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document.addEventListener('touchstart', () => {
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if (type === 'touch') return;
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(type = 'touch'), callback(type), document.addEventListener('mousemove', mousemoveHandler);
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});
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};
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```
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```js
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onUserInputChange(type => {
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console.log('The user is now using', type, 'as an input method.');
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});
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```
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