Ready for Async Rendering

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3FBEZGPS"TZOD3FOEFSJOH 4DSBNCMF !LPCB

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None

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w "QQFOEJY v16.3 Changes

4.

8IBUJT"TZOD3FOEFSJOH

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w 3FBDU'JCFSJTBOVOJUPGXPSL 㲈3FBDU&MFNFOU w *UJTQPTTJCMFUPTUPQBOESFTVNFVQEBUFT 3FDBQ3FBDU'JCFS FiberA FiberB FiberD
FiberE Commit all SideEffects Idle Time Idle Time Idle Time SideEffect SideEffect Host (DOM) FiberC Render Phase Commit Phase

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w 3FOEFS1IBTFʜ"TZOD w $PNNJU1IBTFʜ4ZOD 3FDBQ3FBDU'JCFS FiberA FiberB FiberD FiberE Commit
all SideEffects Idle Time Idle Time Idle Time SideEffect SideEffect Host (DOM) FiberC Async Sync

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4VTQFOEBOE3FTVNF FiberA FiberB FiberA FiberC Commit Low Priority Sync Priority
Commit FiberA FiberB FiberC Low Priority Reuse Interrupt Suspend

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-JGFDZDMF.FUIPET

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$IBOHFTGPSMJGFDZDMFNFUIPET http://blog.koba04.com/post/2018/04/04/react-v163-changes/

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w $BMMFEBU3FOEFS1IBTF w 3FUVSOBQBSUJBMTUBUFCBTFEPOOFYU1SPQT w TUBUJDHFU%FSJWFE4UBUF'SPN1SPQT static getDerivedStateFromProps(nextProps, prevState) {
if (nextProps.category !== prevState.category) { return { data: null, category: null }; } return null; } componentDidUpdate() { if (this.state.category == null) { fetchData(this.props.category).then((data) => { this.setState({category: this.props.category, data}); }); }

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w $BMMFEBU$PNNJU1IBTF w 3FUVSOBTOBQTIPU BOZ CFGPSFVQEBUFUIF)PTU w UIFTOBQTIPUJTQBTTFEUPDPNQPOFOU%JE6QEBUF HFU4OBQTIPU#FGPSF6QEBUF getSnapshotBeforeUpdate()
{ return { scrollHeight: document.body.scrollHeight, scrollTop: document.body.scrollTop, }; } componentDidUpdate(prevProps, prevState, snapshot) { const {body} = document; const {scrollTop, scrollHeight} = snapshot; body.scrollTop = scrollTop + (body.scrollHeight - scrollHeight); }

12.

https://reactjs.org/blog/2018/03/27/update-on-async-rendering.html#examples

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https://github.com/facebook/react/tree/master/packages/create-subscription

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4USJDU.PEF

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w *EFOUJGZJOHDPNQPOFOUTVOTBGFMJGFDZDMFT w 8BSOJOHBCPVUMFHBDZTUSJOHSFG"1*VTBHF w %FUFDUJOHVOFYQFDUFETJEFF⒎FDUT 4USJDU.PEF const {StrictMode} =
React; const App = () => ( <StrictMode> <Header /> <Main /> <Footer /> </StrictMode> );

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/FX$BQBCJMJUJFT

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https://reactjs.org/blog/2018/03/01/sneak-peek-beyond-react-16.html

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5JNF4MJDJOH

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<AsyncMode> <FilterInput onChange={value => { ReactDOM.flushSync(() => this.setState({value})); this.setState({data: this.filterData(value)}); }} /> </AsyncMode>

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https://koba04.github.io/react-ﬁber-resources/examples/ Async Update Sync Update

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None

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https://zeit.co/blog/domains-search-web

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3FBDU4VTQFOTF

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https://github.com/facebook/react/pull/12279

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"1*4VDDFTT &SSPSʜ w .BOZMPBEJOHTQJOOFST KBOLCZBGBTUSFTQPOTF 3FBDU4VTQFOTF

26.

3FBDU4VTQFOTF "1*XJMMCFDIBOHFE import SimpleCacheProvider from ‘simple-cache-provider’; const cache = SimpleCacheProvider.createCache();
const userFetcher = id => SimpleCacheProvider.createResource(id => fetch(`/api/users/${id}`).then(res => res.json()); )(cache, id); const User = props => { const user = userFetcher.read(props.id); return <div>{user.name}</div>; }; const Fallback = props => ( <React.Timeout ms={props.timeout}> {didExpire => didExpire ? props.placeholder : props.children} </React.Timeout> ); <Fallback placeholder=“Loading…” timeout={200}> <User id={100} /> </Fallback>

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3FBDU4VTQFOTF "1*XJMMCFDIBOHFE import SimpleCacheProvider from ‘simple-cache-provider’; const cache = SimpleCacheProvider.createCache();
const routeFetcher = Component => SimpleCacheProvider.createResource(Component => import(Component).then(module => module.default); )(cache, Component); const UserPage = () => { const Component = routeFetcher.read(‘./pages/User’); return <Component />; }; const Fallback = props => ( <React.Timeout ms={props.timeout}> {didExpire => didExpire ? props.placeholder : props.children} </React.Timeout> ); <Fallback placeholder=“Loading…” timeout={1000}> <UserPage /> </Fallback>

28.

Empty Pending Resolved Rejected read or preload throw promise return
value from cache Cache load

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w 3FBDU4VTQFOTFJTCBTFEPO&SSPS#PVOEBSJFT UIPVHI XIJDIUISPXT1SPNJTFJOTUFBEPG&SSPS )PXEPFT3FBDU4VTQFOTFXPSL User Fallback Timeout throw Promise!
(suspend) timeout render with fetched Data (resume)

30.

https://github.com/facebook/react/pull/12201

31.

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/FX$POUFYU"1* const LangContext = React.createContext(‘en’); const ThemeContext = React.createContext(‘dark’); const
App = () => ( <LangContext.Provider value=“en”> <ThemeContext.Provider value=“dark”> <Child> <LangContext.Consumer>  {lang => ( <ThemeContext.Consumer> {theme => ( <button className={theme}> {getMessage(‘click’, lang)} </button> )} </ThemeContext.Consumer> )} </LangContext.Consumer> </Child> </ThemeContext.Provider> </LangContext.Provider> );

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w )BSEUPUZQFDIFDLJOH w TIPVME$PNQPOFOU6QEBUFNJHIUCSFBLUIFVQEBUF 1SPCMFNTPGMFHBDZ$POUFYU"1* GrandChild Child Parent ThemeContext Brown
-> Orange shouldComponentUpdate return false;

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w 0QUJNJ[FUIFVQEBUFTGPS$POUFYUWBMVF w 3FBDUVTFTCJUXJTFPQFSBUPSJUTJOUFSOBMT 0CTFSWFE#JUT VOTUBCMF⚠ const StoreContext = React.createContext(null,
(prev, next) => { let changedBits = 0; if (prev.foo !== next.foo) changedBits |= 0b01; if (prev.bar !== next.bar) changedBits |= 0b10; return changedBits; }); // changedBits & unstable_observedBits !== 0 <StoreContext.Consumer unstable_observedBits={0b01}> {({foo}) => <div>{foo}</div> </StoreContext.Consumer> <StoreContext.Consumer unstable_observedBits={0b10}> {({bar}) => <div>{bar}</div> </StoreContext.Consumer>

36.

https://medium.com/@koba04/a-secret-parts-of-react-new-context-api-e9506a4578aa

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Ready for Async Rendering

Ready for Async Rendering

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