Line-wise standard streams

[ehmicky]

With #695, we just added line-wise transforms. However, this does not cover childProcess.std*.

const childProcess = execa('...')
for await (const chunk of childProcess.stdout) {
  console.log(chunk) // Buffer, and not line-wise
}

What are your thoughts on adding the following?

const childProcess = execa('...', {lines: true})
for await (const line of childProcess.stdout) {
  console.log(line) // String, and line-wise
}

This would work also for childProcess.stdout.read(), childProcess.stdout.on('data') and when redirecting from/to Node.js/web streams.

const writableStream = new Writable({
  write(line, encoding, done) {
    console.log(line) // String, and line-wise
    done()
  }
})
await execa('...', {lines: true, stdout: writableStream})

This would be pretty fairly simple to implement since it can re-use most of the logic of 2 separate features:

• Line-wise transforms (Line-wise transforms #695)
• objectMode transform (Allow transform streams convert output to an array of any objects, instead of a single string #21)

Under the hood, when the lines: true option is used, we would just add an internal transform that is a noop, but is both line-wise and in objectMode.

[sindresorhus]

Yes, this would be nice 👍