Examples of reading and writing streams

Node.js

const { Readable, Writable } = require("stream");

const inStream = new Readable();

inStream.push(Buffer.from("foo"));
inStream.push(Buffer.from("bar"));
inStream.push(null); // end stream
inStream.pipe(process.stdout);

const outStream = new Writable({
  write(chunk, encoding, callback) {
    console.log("received: " + chunk.toString("utf8"));
    callback();
  },
});

outStream.write(Buffer.from("abc"));
outStream.write(Buffer.from("xyz"));
outStream.end();

Output

foobar
received: abc
received: xyz

Go

package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"os"
	"runtime"
)

func main() {
	inStream := new(bytes.Buffer)
	w := bufio.NewWriter(inStream)
	_, err := w.Write([]byte("foo"))
	if err != nil {
		panic(err)
	}
	_, err = w.Write([]byte("bar"))
	if err != nil {
		panic(err)
	}
	err = w.Flush()
	if err != nil {
		panic(err)
	}

	inStream.WriteTo(os.Stdout)
	fmt.Print("\n")

	outStream := new(bytes.Buffer)
	outStream.Write([]byte("abc\n"))
	outStream.Write([]byte("xyc\n"))
	piper, pipew := io.Pipe()

	go func() {
		sc := bufio.NewScanner(piper)
		for sc.Scan() {
			fmt.Println("received: " + sc.Text())
		}
		if err := sc.Err(); err != nil {
			panic(err)
		}

		os.Exit(0)
	}()

	go func() {
		defer pipew.Close()
		io.Copy(pipew, outStream)
	}()

	defer runtime.Goexit()
}

Output

foobar
received: abc
received: xyc

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