rxjs-stream
Note With the addition of Async Iternables, this library is no longer necessary.
This is a simple library for converting to and from NodeJS stream and RxJS 7.
This was created to fill the gap left by rx-node, which only works with rxjs 4.
Installation
npm install --save rxjs rxjs-stream
Usage
Writing to a stream.
import { rxToStream } from 'rxjs-stream';
let data = 'This is a bit of text to have some fun with';
let src = Rx.Observable.from(data.split(' '));
rxToStream(src).pipe(process.stdout);
Writing objects to a stream
To write objects, you must pass in the ReadableOptions
with objectMode
to be true: { objectMode: true }
import { rxToStream } from 'rxjs-stream';
let data = 'This is a bit of text to have some fun with';
let wordObj = data.split(' ').map((text) => ({ text }));
let src = Rx.Observable.from(wordObj);
let stream = rxToStream(src, { objectMode: true });
Read from a stream
import { rxToStream, streamToStringRx } from 'rxjs-stream';
// Read stdin and make it upper case then send it to stdout
let ob = streamToStringRx(process.stdin).map((text) => text.toUpperCase());
rxToStream(ob).pipe(process.stdout);
Performance
It is recommended to buffer observable values before sending them to the stream. Node streams work better with fewer calls of a large amount of data than with many calls with a small amount of data.
Example:
import * as loremIpsum from 'lorem-ipsum';
import { rxToStream } from 'rxjs-stream';
let book = loremIpsum({ count: 1000, format: 'plain', units: 'paragraphs' });
let words = Rx.Observable.from(book.split(/\b/));
let wordsBuffered = words.bufferCount(1000).map((words) => words.join(''));
let stream = rxToStream(wordsBuffered);
stream.pipe(process.stdout);
Compatibility
This library is tested with Node 12 and above.
rx-stream | RxJS | Node |
---|---|---|
4.x | 7.x | >=12 |
3.x | 6.x | >=10 |