Memstreams NPM

Memory Stream

npm type definitions GitHub

Memory Streams library for JavaScript based on readable-stream
This library is forked from stream-mock

Features

Create a readable stream from any iterable.
Create a writable stream that puts its data at your disposal.
Create a duplex stream that combines a readable and writable stream together.
Can operate both in object and normal ( Buffer ) mode.
Forward writable to readable through event write to replace queue

Quick start

yarn add memstreams

Or, if you are more a npm person

npm i memstreams

Basic usage

You are building an awesome brand new Transform stream that rounds all your values.

rounder.ts

import {Transform} from 'stream';

export class Rounder extends Transform {
  _transform(chunk, encoding, callback) {
    this.push(Math.round(chunk));
    callback();
  }
}

Now you need / want to test it.

example.ts

import {ObjectReader, ObjectWriter} from 'memstreams';
import {Rounder} from './rounder';

const input = [1.2, 2.6, 3.7];
const transform = new Rounder({objectMode: true});
const reader = new ObjectReader(input, {autoEnd: true});
const writer = new ObjectWriter();

reader.pipe(transform).pipe(writer);

writer.on('finish', () => {
  console.log(writer.data);
});