fs: add 'close' event to FSWatcher

[aleclarson]

Should process.nextTick wrap this? Are tests necessary here?

• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

[mscdex]

A test would be good, yes.

[cjihrig]

Docs are needed as well.

[mcollina]

Why do you need a 'close'  event? I'm not against this, I just want to understand better.
close() seems to be a synchronous operation.

[aleclarson]

@mcollina To keep the close logic in the same function as fs.watch(). The watcher's close method is called from multiple places.

function watch(root) {
  return fs.watch(root, (evt, file) => {
    // ...
  }).on('close', () => {
    // ...
  })
}

Currently, I'm monkey-patching the close method.

function watch(root) {
  let watcher = fs.watch(root, (evt, file) => {
    // ...
  })
  let {close} = watcher
  watcher.close = function() {
    close.call(watcher)
    // ...
  }
  return watcher
}

[mcollina]

@aleclarson definitely better. Can you add a unit test?

[aleclarson]

Added a test and docs. Note the <!-- YAML added: v --> is missing.

[mcollina]

@aleclarson the <!-- YAML added: v -->  should be added. Use REPLACEME as the version.

[cjihrig]

You can drop the closeCount, and just write watcher.on('close', common.mustCall());

[aleclarson]

Does that protect against multiple calls?

[cjihrig]

Yes

[aleclarson]

Good to go 👍

[mcollina]

LGTM

[bnoordhuis]

Can you wrap this in a process.nextTick()? Zalgo and all that.

[BridgeAR]

Ping @aleclarson

[aleclarson]

Now wrapped with process.nextTick

[jasnell]

CI: https://ci.nodejs.org/job/node-test-pull-request/14291/

[lpinca]

Landed in 5cc948b.