140 lines
3.8 KiB
JavaScript
140 lines
3.8 KiB
JavaScript
// @flow
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import ArrowKeyNavigation from "boundless-arrow-key-navigation";
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import { isEqual } from "lodash";
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import { observable, action } from "mobx";
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import { observer } from "mobx-react";
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import * as React from "react";
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import { Waypoint } from "react-waypoint";
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import { DEFAULT_PAGINATION_LIMIT } from "stores/BaseStore";
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import DelayedMount from "components/DelayedMount";
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import { ListPlaceholder } from "components/LoadingPlaceholder";
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type Props = {
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fetch?: (options: ?Object) => Promise<void>,
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options?: Object,
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heading?: React.Node,
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empty?: React.Node,
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items: any[],
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renderItem: (any) => React.Node,
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};
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@observer
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class PaginatedList extends React.Component<Props> {
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isInitiallyLoaded: boolean = false;
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@observable isLoaded: boolean = false;
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@observable isFetchingMore: boolean = false;
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@observable isFetching: boolean = false;
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@observable renderCount: number = DEFAULT_PAGINATION_LIMIT;
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@observable offset: number = 0;
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@observable allowLoadMore: boolean = true;
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constructor(props: Props) {
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super(props);
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this.isInitiallyLoaded = this.props.items.length > 0;
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}
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componentDidMount() {
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this.fetchResults();
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}
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componentDidUpdate(prevProps: Props) {
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if (
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prevProps.fetch !== this.props.fetch ||
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!isEqual(prevProps.options, this.props.options)
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) {
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this.reset();
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this.fetchResults();
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}
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}
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reset = () => {
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this.offset = 0;
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this.allowLoadMore = true;
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this.renderCount = DEFAULT_PAGINATION_LIMIT;
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this.isFetching = false;
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this.isFetchingMore = false;
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this.isLoaded = false;
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};
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fetchResults = async () => {
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if (!this.props.fetch) return;
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this.isFetching = true;
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const limit = DEFAULT_PAGINATION_LIMIT;
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const results = await this.props.fetch({
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limit,
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offset: this.offset,
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...this.props.options,
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});
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if (results && (results.length === 0 || results.length < limit)) {
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this.allowLoadMore = false;
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} else {
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this.offset += limit;
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}
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this.renderCount += limit;
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this.isLoaded = true;
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this.isFetching = false;
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this.isFetchingMore = false;
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};
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@action
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loadMoreResults = async () => {
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// Don't paginate if there aren't more results or we’re currently fetching
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if (!this.allowLoadMore || this.isFetching) return;
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// If there are already cached results that we haven't yet rendered because
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// of lazy rendering then show another page.
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const leftToRender = this.props.items.length - this.renderCount;
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if (leftToRender > 1) {
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this.renderCount += DEFAULT_PAGINATION_LIMIT;
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}
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// If there are less than a pages results in the cache go ahead and fetch
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// another page from the server
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if (leftToRender <= DEFAULT_PAGINATION_LIMIT) {
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this.isFetchingMore = true;
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await this.fetchResults();
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}
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};
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render() {
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const { items, heading, empty } = this.props;
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const showLoading =
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this.isFetching && !this.isFetchingMore && !this.isInitiallyLoaded;
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const showEmpty = !items.length && !showLoading;
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const showList =
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(this.isLoaded || this.isInitiallyLoaded) && !showLoading && !showEmpty;
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return (
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<>
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{showEmpty && empty}
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{showList && (
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<>
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{heading}
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<ArrowKeyNavigation
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mode={ArrowKeyNavigation.mode.VERTICAL}
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defaultActiveChildIndex={0}
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>
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{items.slice(0, this.renderCount).map(this.props.renderItem)}
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</ArrowKeyNavigation>
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{this.allowLoadMore && (
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<Waypoint key={this.renderCount} onEnter={this.loadMoreResults} />
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)}
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</>
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)}
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{showLoading && (
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<DelayedMount>
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<ListPlaceholder count={5} />
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</DelayedMount>
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)}
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</>
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);
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}
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}
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export default PaginatedList;
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