Dynamically generate a file download in express without touching the filesystem

gistfile1.js

var express = require('express');
var app = require('express').createServer();
app.listen('3030');
app.get('/', function(req, res) {
  res.contentType('text/plain');
  res.send('This is the content', { 'Content-Disposition': 'attachment; filename=name.txt' }); 
});

Express 4:

app.get('/', async (req, res) => {
    res.status(200)
        .attachment(`name.txt`)
        .send('This is the content')
})