node/test/parallel/test-stream-await-drain-writers-in-synchronously-recursion-write.js

'use strict';
const common = require('../common');
const { PassThrough } = require('stream');

const encode = new PassThrough({
  highWaterMark: 1
});

const decode = new PassThrough({
  highWaterMark: 1
});

const send = common.mustCall((buf) => {
  encode.write(buf);
}, 4);

let i = 0;
const onData = common.mustCall(() => {
  if (++i === 2) {
    send(Buffer.from([0x3]));
    send(Buffer.from([0x4]));
  }
}, 4);

encode.pipe(decode).on('data', onData);

send(Buffer.from([0x1]));
send(Buffer.from([0x2]));