Rxnode — reactive nodejs API

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At the beginning of 2020, my career as a frontend developer turned in an unexpected direction for me. I haven’t written a single Angular component in a year. I Replaced Angular with server code and code for the CLI. It was a new and interesting experience for me, but it wasn’t easy to solve my usual tasks without RxJS.

Let’s look at a simple example of reading and writing a file using the native features of nodejs

import { readFile, writeFile } from 'fs';

readFile('src/some-file.js', (error, data) => {
  if (error) {
    console.error(error);
    return;
  }

  writeFile('src/some-file.js', data, (error) => {
    if (error) {
      console.error(error);
      return;
    }

    console.log('Success!');
  });
});

Code with callbacks after Angular seems complicated. First, I translated callbacks to promises.

import * as fs from 'fs';
import { promisify } from 'util';

const readFile = promisify(fs.readFile);
const writeFile = promisify(fs.writeFile);

readFile('src/some-file.js')
  .then((data) => writeFile('src/some-file.js', data))
  .then(() => {
    console.log('Success!');
  })
  .cacth(console.error);

I was OK with this solution until I needed to implement several tasks’ competitive execution with a limit. RxJS has such an opportunity out of the box. Why would I invent my own algorithm…