Sequentally read arbitrary chunks of exactly desired amount of data from any ReadableStream
var readNext = require('sequentalreader')(process.stdin);
readNext(10)
.then((res) => {
if (res === null) console.log('EOF');
console.log('first 10 characters: %s', res);
return readNext(5);
})
.then((res) => {
if (res === null) console.log('EOF');
console.log('next 5 characters: %s', res);
});