| 1 | import React from 'react'; |
| 2 | import {useContext, useMemo, useRef, useState, useLayoutEffect} from 'react'; |
| 3 | import {__RouterContext} from 'react-router'; |
| 4 | import {ReactReduxContext} from 'react-redux'; |
| 5 | |
| 6 | import ThemeContext from './shared/ThemeContext'; |
| 7 | |
| 8 | let rendererModule = { |
| 9 | status: 'pending', |
| 10 | promise: null, |
| 11 | result: null, |
| 12 | }; |
| 13 | |
| 14 | export default function lazyLegacyRoot(getLegacyComponent) { |
| 15 | let componentModule = { |
| 16 | status: 'pending', |
| 17 | promise: null, |
| 18 | result: null, |
| 19 | }; |
| 20 | |
| 21 | return function Wrapper(props) { |
| 22 | const createLegacyRoot = readModule( |
| 23 | rendererModule, |
| 24 | () => import('../legacy/createLegacyRoot') |
| 25 | ).default; |
| 26 | const Component = readModule(componentModule, getLegacyComponent).default; |
| 27 | const containerRef = useRef(null); |
| 28 | const rootRef = useRef(null); |
| 29 | |
| 30 | // Populate every contexts we want the legacy subtree to see. |
| 31 | // Then in src/legacy/createLegacyRoot we will apply them. |
| 32 | const theme = useContext(ThemeContext); |
| 33 | const router = useContext(__RouterContext); |
| 34 | const reactRedux = useContext(ReactReduxContext); |
| 35 | const context = useMemo( |
| 36 | () => ({ |
| 37 | theme, |
| 38 | router, |
| 39 | reactRedux, |
| 40 | }), |
| 41 | [theme, router, reactRedux] |
| 42 | ); |
| 43 | |
| 44 | // Create/unmount. |
| 45 | useLayoutEffect(() => { |
| 46 | if (!rootRef.current) { |
| 47 | rootRef.current = createLegacyRoot(containerRef.current); |
| 48 | } |
| 49 | const root = rootRef.current; |
| 50 | return () => { |
| 51 | root.unmount(); |
| 52 | }; |
| 53 | }, [createLegacyRoot]); |
| 54 | |
| 55 | // Mount/update. |
| 56 | useLayoutEffect(() => { |
| 57 | if (rootRef.current) { |
| 58 | rootRef.current.render(Component, props, context); |
| 59 | } |
| 60 | }, [Component, props, context]); |
| 61 | |
| 62 | return <div style={{display: 'contents'}} ref={containerRef} />; |
| 63 | }; |
| 64 | } |
| 65 | |
| 66 | // This is similar to React.lazy, but implemented manually. |
| 67 | // We use this to Suspend rendering of this component until |
| 68 | // we fetch the component and the legacy React to render it. |
| 69 | function readModule(record, createPromise) { |
| 70 | if (record.status === 'fulfilled') { |
| 71 | return record.result; |
| 72 | } |
| 73 | if (record.status === 'rejected') { |
| 74 | throw record.result; |
| 75 | } |
| 76 | if (!record.promise) { |
| 77 | record.promise = createPromise().then( |
| 78 | value => { |
| 79 | if (record.status === 'pending') { |
| 80 | record.status = 'fulfilled'; |
| 81 | record.promise = null; |
| 82 | record.result = value; |
| 83 | } |
| 84 | }, |
| 85 | error => { |
| 86 | if (record.status === 'pending') { |
| 87 | record.status = 'rejected'; |
| 88 | record.promise = null; |
| 89 | record.result = error; |
| 90 | } |
| 91 | } |
| 92 | ); |
| 93 | } |
| 94 | throw record.promise; |
| 95 | } |