masto-fe/app/javascript/flavours/glitch/components/intersection_observer_article.js
Thibaut Girka fb6f131fa1 Revert 245816ab27 (fixes #348)
Since 245816ab27, IntersectionObserverArticle
assumes that its children do not change unless the number of children changes.

This is not the case with the notification overlay, which resulted in the
checkmark of notification cleaning mode not updating unless scrolling to make
notifications appear/disappear.

This change may negatively impact performances.
2018-02-10 20:59:50 +01:00

128 lines
4.2 KiB
JavaScript

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