const fs = require('fs');
const readAll = require('node-read-all');
 
const rStream = fs.createReadStream('file.txt');
rStream.setEncoding('utf8');
readAll(rStream)
  .then(data => console.log(data))
  .catch(console.error.bind(console));

const { Transform } = require('stream');
const readAll = require('node-read-all');
 
const transformStream = new Transform({
  readableObjectMode: true,
  transform(chunk, encoding, callback) {
    this.push({ value: chunk.toString() });
    callback();
  },
});
 
readAll(transformStream)
  .then(data => console.log(data))
  .catch(console.error.bind(console));
 
setTimeout(() => {
  transformStream.write('a');
  transformStream.write('b');
  transformStream.write('c');
  transformStream.end();
}, 1000);