import PropTypes from 'prop-types'; import { PureComponent } from 'react'; const emptyComponent = () => null; const noop = () => { }; class Bundle extends PureComponent { static propTypes = { fetchComponent: PropTypes.func.isRequired, loading: PropTypes.func, error: PropTypes.func, children: PropTypes.func.isRequired, renderDelay: PropTypes.number, onFetch: PropTypes.func, onFetchSuccess: PropTypes.func, onFetchFail: PropTypes.func, }; static defaultProps = { loading: emptyComponent, error: emptyComponent, renderDelay: 0, onFetch: noop, onFetchSuccess: noop, onFetchFail: noop, }; static cache = new Map; state = { mod: undefined, forceRender: false, }; UNSAFE_componentWillMount() { this.load(this.props); } UNSAFE_componentWillReceiveProps(nextProps) { if (nextProps.fetchComponent !== this.props.fetchComponent) { this.load(nextProps); } } componentWillUnmount () { if (this.timeout) { clearTimeout(this.timeout); } } load = (props) => { const { fetchComponent, onFetch, onFetchSuccess, onFetchFail, renderDelay } = props || this.props; const cachedMod = Bundle.cache.get(fetchComponent); if (fetchComponent === undefined) { this.setState({ mod: null }); return Promise.resolve(); } onFetch(); if (cachedMod) { this.setState({ mod: cachedMod.default }); onFetchSuccess(); return Promise.resolve(); } this.setState({ mod: undefined }); if (renderDelay !== 0) { this.timestamp = new Date(); this.timeout = setTimeout(() => this.setState({ forceRender: true }), renderDelay); } return fetchComponent() .then((mod) => { Bundle.cache.set(fetchComponent, mod); this.setState({ mod: mod.default }); onFetchSuccess(); }) .catch((error) => { this.setState({ mod: null }); onFetchFail(error); }); }; render() { const { loading: Loading, error: Error, children, renderDelay } = this.props; const { mod, forceRender } = this.state; const elapsed = this.timestamp ? (new Date() - this.timestamp) : renderDelay; if (mod === undefined) { return (elapsed >= renderDelay || forceRender) ? <Loading /> : null; } if (mod === null) { return <Error onRetry={this.load} />; } return children(mod); } } export default Bundle;