122 lines
4 KiB
JavaScript
122 lines
4 KiB
JavaScript
import React from 'react';
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import PropTypes from 'prop-types';
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import ImmutablePureComponent from 'react-immutable-pure-component';
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import scheduleIdleTask from '../features/ui/util/schedule_idle_task';
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import getRectFromEntry from '../features/ui/util/get_rect_from_entry';
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export default class IntersectionObserverArticle extends ImmutablePureComponent {
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static propTypes = {
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intersectionObserverWrapper: PropTypes.object,
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id: PropTypes.oneOfType([PropTypes.string, PropTypes.number]),
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index: PropTypes.oneOfType([PropTypes.string, PropTypes.number]),
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listLength: PropTypes.oneOfType([PropTypes.string, PropTypes.number]),
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children: PropTypes.node,
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};
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state = {
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isHidden: false, // set to true in requestIdleCallback to trigger un-render
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}
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shouldComponentUpdate (nextProps, nextState) {
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if (!nextState.isIntersecting && nextState.isHidden) {
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// It's only if we're not intersecting (i.e. offscreen) and isHidden is true
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// that either "isIntersecting" or "isHidden" matter, and then they're
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// the only things that matter (and updated ARIA attributes).
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return this.state.isIntersecting || !this.state.isHidden || nextProps.listLength !== this.props.listLength;
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} else if (nextState.isIntersecting && !this.state.isIntersecting) {
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// If we're going from a non-intersecting state to an intersecting state,
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// (i.e. offscreen to onscreen), then we definitely need to re-render
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return true;
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}
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// Otherwise, diff based on "updateOnProps" and "updateOnStates"
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return super.shouldComponentUpdate(nextProps, nextState);
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}
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componentDidMount () {
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if (!this.props.intersectionObserverWrapper) {
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// TODO: enable IntersectionObserver optimization for notification statuses.
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// These are managed in notifications/index.js rather than status_list.js
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return;
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}
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this.props.intersectionObserverWrapper.observe(
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this.props.id,
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this.node,
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this.handleIntersection
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);
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this.componentMounted = true;
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}
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componentWillUnmount () {
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if (this.props.intersectionObserverWrapper) {
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this.props.intersectionObserverWrapper.unobserve(this.props.id, this.node);
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}
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this.componentMounted = false;
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}
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handleIntersection = (entry) => {
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if (this.node && this.node.children.length !== 0) {
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// save the height of the fully-rendered element
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this.height = getRectFromEntry(entry).height;
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if (this.props.onHeightChange) {
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this.props.onHeightChange(this.props.status, this.height);
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}
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}
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this.setState((prevState) => {
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if (prevState.isIntersecting && !entry.isIntersecting) {
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scheduleIdleTask(this.hideIfNotIntersecting);
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}
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return {
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isIntersecting: entry.isIntersecting,
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isHidden: false,
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};
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});
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}
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hideIfNotIntersecting = () => {
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if (!this.componentMounted) {
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return;
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}
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// When the browser gets a chance, test if we're still not intersecting,
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// and if so, set our isHidden to true to trigger an unrender. The point of
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// this is to save DOM nodes and avoid using up too much memory.
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// See: https://github.com/tootsuite/mastodon/issues/2900
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this.setState((prevState) => ({ isHidden: !prevState.isIntersecting }));
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}
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handleRef = (node) => {
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this.node = node;
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}
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render () {
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const { children, id, index, listLength } = this.props;
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const { isIntersecting, isHidden } = this.state;
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if (!isIntersecting && isHidden) {
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return (
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<article
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ref={this.handleRef}
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aria-posinset={index}
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aria-setsize={listLength}
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style={{ height: `${this.height}px`, opacity: 0, overflow: 'hidden' }}
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data-id={id}
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tabIndex='0'
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>
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{children && React.cloneElement(children, { hidden: true })}
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</article>
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);
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}
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return (
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<article ref={this.handleRef} aria-posinset={index} aria-setsize={listLength} data-id={id} tabIndex='0'>
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{children && React.cloneElement(children, { hidden: false })}
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</article>
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);
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}
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}
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