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Kostia Palchyk
Kostia Palchyk

Posted on • Edited on

What React RxJS libs do You Use?

#discuss #react #rxjs #javascript

I'm currently using redux-observable for effects. It fits nice into whole redux flow (the question is if I need Redux itself, but that's a separate matter)

Sometimes I use RxJS directly in an effect hook (surely, with teardown!), but there are RxJS hook libraries for that, e.g.: re-rxjs/react-rxjs, crimx/observable-hooks and LeetCode-OpenSource/rxjs-hooks (they have thousands of weekly downloads! Alas, I haven't tried them well yet)

And I made a tiny React + RxJS package to display Observable content:

import React from 'react';
import { $ } from 'react-rxjs-elements';

function App(){
  return <div>
    <$>{ timer(0, 1000) } sec</$>
  </div>
}
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npm i react-rxjs-elements

P.S. I also created an ⚠️ experimental JSX + RxJS framework — it's cute, check it out!

And what RxJS + React addons do you use?
How do you like them? Share an example!
Do you think we even need RxJS in React?

I'm listening

Share your thoughts!

Top comments (3)

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wolfhoundjesse profile image
Jesse M. Holmes • • Edited

If I wanted to return an array of JSX, is there a better way than:

const api1$ = useMemo(() => 
  fromFetch('http://api1.dev').pipe(
    mergeMap(res => res.json())
  ),[])

const api2$ = useMemo(() => 
  fromFetch('http://api2.dev').pipe(
    mergeMap(res => res.json())
  ),[])

const services$ = useMemo(() =>
  forkJoin([api1$, api2$])
),[])

return <$>{ services$.pipe(
  map(items => items.map(
    item => <p key={item.id}> {item.description} </p>
  ))
)}
</$>
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kosich profile image
Kostia Palchyk • • Edited

Hey, Jesse!

Great question, a lot happening here :)

First, about observables inside render fn:

useMemo is fine, but it does not guarantee that the content will be preserved. Consider either using some useConst analogue, or moving Observables outside the render function.

const Component = () => {
  let time$ = useConst(() => timer(0, 1000));

  return <$div>{ timer$ }</$div>
};
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Also, check out this experimental update to the <$> library:

const Component = createComponent$(() => {
  let time$ = timer(0, 1000);

  return <$div>{ timer$ }</$div>
});
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The component function is executed only once, thus making it safe to create Observables here. This is a beta feature and I'm currently testing it. It's available in the @next npm version and can be trialled online More details at github/react-rxjs-elements/pull/9

Second, the double mapping

The services$.pipe( map(items => items.map( … thing always bothered me. There are also several solutions to it.

1: Use a separate component to render the list

function App() {
  let source$ = useConst(() => getData('/url/to/data'));

  return <$>{
    source$.pipe(
      map(response => <List items={response}/>)
    )
  }</$>
}
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2: Use rxjs-proxify to do the array.map in a more concise way:

export function App() {
  let source = useConst(() => proxify(getData('/url/to/data')));

  return <ul>
    <$>{
      source.map(i =>
        <li key={i.key}>{i.title}</li>
      )
    }</$>
  </ul>;
}
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Try this example in online playground

Proxify provides magic like proxify( of(42) ).toString() which returns an Observable<string>. So .map(…) in the example above creates another Observable, by calling .pipe(map( items => items.map(…) )) on the underlying Observable. More on the rxjs-proxify here

-

And just a side note: use ajax from rxjs/ajax to remove the

fromFetch('http://api2.dev').pipe(
  mergeMap(res => res.json())
);
// ≈
ajax('http://api2.dev');
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-

If that doesn't suit your needs — be sure to checkout other libs I mention, they are all pretty amazing.

Cheers 🙂

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kosich profile image
Kostia Palchyk • • Edited

Some honorable mentions:

<Stream source={source$}>
  {values => <div>{values.message}</div>}
</Stream>
  • refract

Handle your component effects and side-effects in a clear and declarative fashion by using asynchronous data streams (reactive programming).

github.com/fanduel-oss/refract

Cool "implement it from scratch" tutorial on using React with RxJS

daslaf image

Using React and RxJS together

Osman Cea ・ Jun 3 ・ 8 min read

#rxjs #react #javascript #frontend

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