React-RxJS

React-RxJS Logo

React bindings for RxJS

[![Build Status](https://img.shields.io/travis/re-rxjs/react-rxjs.svg?style=flat-square)](https://travis-ci.org/re-rxjs/react-rxjs) [![codecov](https://img.shields.io/codecov/c/github/re-rxjs/react-rxjs.svg?style=flat-square)](https://codecov.io/gh/re-rxjs/react-rxjs) [![version](https://img.shields.io/npm/v/react-rxjs.svg?style=flat-square)](https://www.npmjs.com/package/react-rxjs) [![MIT License](https://img.shields.io/npm/l/react-rxjs.svg?style=flat-square)](https://github.com/re-rxjs/react-rxjs/blob/main/LICENSE) [![All Contributors](https://img.shields.io/badge/all_contributors-5-orange.svg?style=flat-square)](#contributors-) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat-square)](http://makeapullrequest.com) [![Code of Conduct](https://img.shields.io/badge/code%20of-conduct-ff69b4.svg?style=flat-square)](https://github.com/re-rxjs/react-rxjs/blob/main/CODE_OF_CONDUCT.md) Main features ------------- - :cyclone: Truly Reactive - :zap: Highly performant and free of memory-leaks - :twisted_rightwards_arrows: First class support for React Suspense and [ready for Concurrent Mode](https://github.com/dai-shi/will-this-react-global-state-work-in-concurrent-mode#results) - :scissors: Decentralized and composable, thus enabling optimal code-splitting - :microscope: [Tiny and tree-shakeable](https://bundlephobia.com/result?p=react-rxjs) - :muscle: Supports TypeScript ## Table of Contents - [Installation](#installation) - [API](#api) - Core - [connectObservable](#connectObservable) - [connectFactoryObservable](#connectFactoryObservable) - [shareLatest](#shareLatest) - React Suspense Support - [SUSPENSE](#SUSPENSE) - [suspend](#suspend) - [suspended](#suspended) - [switchMapSuspended](#switchMapSuspended) - Utils - [createInput](#createInput) - [Examples](#examples) ## Installation npm install react-rxjs ## API ### connectObservable ```ts const [useCounter, sharedCounter$] = connectObservable( clicks$.pipe( scan(prev => prev + 1, 0), startWith(0), ) ) ``` Accepts: An Observable. Returns `[1, 2]` 1. A React Hook that yields the latest emitted value of the observable. If the Observable doesn't synchronously emit a value upon the first subscription, then the hook will leverage React Suspense while it's waiting for the first value. 2. A `sharedLatest` version of the observable that does not complete. It can be used for composing other streams that depend on it. The shared subscription is closed as soon as there are no subscribers to that observable. ### connectFactoryObservable ```tsx const [useStory, getStory$] = connectFactoryObservable( (storyId: number) => getStoryWithUpdates$(storyId) ) const Story: React.FC<{id: number}> = ({id}) => { const story = useStory(id); return (

{story.title}

{story.description

) } ``` Accepts: A factory function that returns an Observable. Returns `[1, 2]` 1. A React Hook function with the same parameters as the factory function. This hook will yield the latest update from the observable returned from the factory function. If the Observable doesn't synchronously emit a value upon the first subscription, then the hook will leverage React Suspense while it's waiting for the first value. 2. A `sharedLatest` version of the observable returned by the factory function that does not complete. It can be used for composing other streams that depend on it. The shared subscription is closed as soon as there are no subscribers to that observable. ### shareLatest ```ts const activePlanetName$ = planet$.pipe( filter(planet => planet.isActive), map(planet => planet.name), shareLatest() ) ``` A RxJS pipeable operator which shares and replays the latest emitted value. It's the equivalent of: ```ts const shareLatest = (): Observable => source$.pipe( multicast(() => new ReplaySubject(1)), refCount(), ) ``` The enhanced observables returned from `connectObservable` and `connectFactoryObservable` have been enhanced with this operator, but do not complete. Meaning that the latest emitted value will be available until the `refCount` drops to zero. ### SUSPENSE ```ts const story$ = selectedStoryId$.pipe( switchMap(id => concat( SUSPENSE, getStory$(id) )) ) ``` This is a special symbol that can be emitted from our observables to let the react hook know that there is a value on its way, and that we want to leverage React Suspense while we are waiting for that value. ### suspend ```ts const story$ = selectedStoryId$.pipe( switchMap(id => suspend(getStory$(id)) ) ``` A RxJS creation operator that prepends a `SUSPENSE` on the source observable. ### suspended ```ts const story$ = selectedStoryId$.pipe( switchMap(id => getStory$(id).pipe( suspended() )) ) ``` The pipeable version of `suspend` ### switchMapSuspended ```ts const story$ = selectedStoryId$.pipe( switchMapSuspended(getStory$) ) ``` Like `switchMap` but applying a `startWith(SUSPENSE)` to the inner observable. ### createInput A couple examples are worth a thousand words: ```tsx const [getCounter$, setCounter] = createInput(0) const useCounter = connectFactoryObservable((id: string) => getCounter$(id)) const Counter: React.FC<{id: string}> = ({id}) => { const counter = useCounter(id); return ( {counter} merge( getUpClicks$(id).pipe(mapTo(1)), getDownClicks$(id).pipe(mapTo(-1)), ).pipe( scan((a, b) => a + b, 0), startWith(0) ) ) const Counter: React.FC<{id: string}> = ({id}) => { const counter = useCounter(id); return ( {counter} () const onSubmit = (value: string) => searchInput$.next(value) const findRepos = (query: string): Promise => fetch(`https://api.github.com/search/repositories?q=${query}`) .then(response => response.json()) .then(rawData => (rawData.items ?? []).map((repo: any) => ({ id: repo.id, name: repo.name, description: repo.description, author: repo.owner.login, stars: repo.stargazers_count, lastUpdate: Date.parse(repo.update_at), })), ) const [useRepos, repos$] = connectObservable( searchInput$.pipe( switchMapSuspended(findRepos), startWith(null), ), ) function Repos() { const repos = useRepos() if (repos === null) { return null } if (repos.length === 0) { return
No results were found.
} return (
    {repos.map(repo => (
    • ))}
) } const [useMostRecentlyUpdatedRepo] = connectObservable( repos$.pipe( map(repos => Array.isArray(repos) && repos.length > 0 ? repos.reduce((winner, current) => current.lastUpdate > winner.lastUpdate ? current : winner, ) : null, ), ), ) function MostRecentlyUpdatedRepo() { const mostRecent = useMostRecentlyUpdatedRepo() if (mostRecent === null) { return null } const { id, name } = mostRecent return (
The most recently updated repo is {name}
) } export default function App() { return ( <>
Search Github Repos
}> ) } ``` ## Contributors ✨ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/docs/en/emoji-key)):

Josep M Sobrepere
πŸ’» πŸ€” 🚧 ⚠️ πŸ‘€ πŸ“–
VΓ­ctor Oliva
πŸ€” πŸ‘€ πŸ’» ⚠️ πŸ“–
Ed
🎨
Pierre Grimaud
πŸ“–
Bhavesh Desai
πŸ‘€ πŸ“– ⚠️
This project follows the [all-contributors](https://github.com/all-contributors/all-contributors) specification. Contributions of any kind welcome!