56 lines
1.6 KiB
JavaScript
56 lines
1.6 KiB
JavaScript
// @flow
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import React, { useEffect, useState } from 'react';
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import { isIosMobileBrowser } from '../../../base/environment/utils';
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/**
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* Component that renders an element to lift the chat input above the Safari keyboard,
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* computing the appropriate height comparisons based on the {@code visualViewport}.
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*
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* @returns {ReactElement}
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*/
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function KeyboardAvoider() {
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if (!isIosMobileBrowser()) {
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return null;
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}
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const [ elementHeight, setElementHeight ] = useState(0);
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const [ storedHeight, setStoredHeight ] = useState(window.innerHeight);
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/**
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* Handles the resizing of the visual viewport in order to compute
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* the {@code KeyboardAvoider}'s height.
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*
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* @returns {void}
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*/
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function handleViewportResize() {
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const { innerWidth, visualViewport: { width, height } } = window;
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// Compare the widths to make sure the {@code visualViewport} didn't resize due to zooming.
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if (width === innerWidth) {
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if (height < storedHeight) {
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setElementHeight(storedHeight - height);
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} else {
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setElementHeight(0);
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}
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setStoredHeight(height);
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}
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}
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useEffect(() => {
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// Call the handler in case the keyboard is open when the {@code KeyboardAvoider} is mounted.
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handleViewportResize();
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window.visualViewport.addEventListener('resize', handleViewportResize);
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return () => {
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window.visualViewport.removeEventListener('resize', handleViewportResize);
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};
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}, []);
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return <div style = {{ height: `${elementHeight}px` }} />;
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}
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export default KeyboardAvoider;
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