fix: wait for flush to finish

[ronag]

Refs: pinojs/pino#1261

[ronag]

Checking for flushing here won't help us to avoid MAX_STRING length on buf.

[ronag]

This doesn't make sense?

[mcollina]

It did. There is a flush scheduled in nextTick where this was correctly reset.

[ronag]

@mcollina PTAL

[coveralls]

Pull Request Test Coverage Report for Build 1564728806

• 15 of 18 (83.33%) changed or added relevant lines in 1 file are covered.
• 7 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-1.1%) to 82.974%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
index.js	15	18	83.33%

Files with Coverage Reduction	New Missed Lines	%
index.js	7	84.26%

Totals
Change from base Build 1558216733:	-1.1%
Covered Lines:	282
Relevant Lines:	332

---

💛 - Coveralls

[ronag]

#56

[ronag]

@mcollina I added a test that fails on main

[mcollina]

I would need to look into this with a couple of free hours. This logic is quite tricky. I'll get to it next week.

[mcollina]

I have tried running the attached test to this PR and it passes on main.

[mcollina]

I was able to repro with:

'use strict'

const t = require('tap')
const { join } = require('path')
const { file } = require('./helper')
const { createReadStream } = require('fs')
const ThreadStream = require('..')
const buffer = require('buffer')

const MAX_STRING = buffer.constants.MAX_STRING_LENGTH

t.plan(1)

const dest = file()
const stream = new ThreadStream({
  filename: join(__dirname, 'to-file.js'),
  workerData: { dest },
  sync: false
})

stream.on('close', async () => {
  t.comment('close emitted')
  let buf
  for await (const chunk of createReadStream(dest)) {
    buf = chunk
  }
  t.equal('asd', buf.toString().slice(-3))
})

stream.on('open', () => {
  t.comment('open emitted')
  stream.write('a'.repeat(MAX_STRING - 2))
  stream.write('asd')
  stream.end()
})

[mcollina]

My bad, I made a mistake in the previous example. We emit 'ready' and not 'open'.

I cannot reproduce the problem using the attached test.

[ronag]

You are right I had not updated my local main.