Rich-Harris

const fs = require('fs');
const { ReadableStream, TransformStream, WritableStream} = require('web-streams-polyfill/ponyfill/es2018');

function createReadStream(file, opts) {
  return new ReadableStream({
    start(controller) {
      const stream = fs.createReadStream(file, opts);
      stream.on('readable', () => {
        const data = stream.read();
        controller.enqueue(data);