JAVASCRIPT

stream in node.js

streams is process(read and write) data piece(chunks) without completing the
whole read or write operation, and therefore without keeping all the data in 
memory.
There are four types of streams => readable streams, writable streams, duplex
and transform streams.

nodejs create stream

const { Readable } = require("stream")

const readable = Readable.from(["input string"])

readable.on("data", (chunk) => {
  console.log(chunk) // will be called once with `"input string"`
})

nodejs stream

const stream = require('stream')
const fs = require('fs')

const html = "<h1> Hello Wordl </h1>

// read file from string and write file
const stream = new Stream()
stream.pipe = function (dest) {
  dest.write(html)
  return dest
}
stream.pipe(createWriteStream(resolve(process.cwd(), 'index.html'), 'utf8'))

// read file from directory and write file
fs.createReadStream('testing.html')
 .pipe(createWriteStream(resolve(process.cwd(), 'index.html'), 'utf8'))