timers: give Timeouts a constructor name

[Fishrock123]

Pull Request check-list

• Does make -j8 test (UNIX) or vcbuild test nosign (Windows) pass with
  this change (including linting)?
• Is the commit message formatted according to CONTRIBUTING.md?

Affected core subsystem(s)

timers

Description of change

Refs: #5792

No functional difference, this is for clarity only.

[cjihrig]

LGTM

[Trott]

LGTM

[jasnell]

LGTM

[jasnell]

should be safe for v4, no?

[benjamingr]

Any reason not to make it a class Timeout?

class Timeout {
  constructor(after) {
    this._called = false;
    this._idleTimeout = after;
    this._idlePrev = this;
    this._idleNext = this;
    this._idleStart = null;
    this._onTimeout = null;
    this._repeat = null;
  }
  unref () {
    if (this._handle) {
      this._handle.unref();
    } else if (typeof this._onTimeout === 'function') {
      var now = TimerWrap.now();
      if (!this._idleStart) this._idleStart = now;
      var delay = this._idleStart + this._idleTimeout - now;
      if (delay < 0) delay = 0;

      // Prevent running cb again when unref() is called during the same cb
      if (this._called && !this._repeat) {
        exports.unenroll(this);
        return;
      }

      var handle = reuse(this);

      this._handle = handle || new TimerWrap();
      this._handle.owner = this;
      this._handle[kOnTimeout] = function unrefdHandle() {
        this.owner._onTimeout();
        if (!this.owner._repeat)
          this.owner.close();
      };
      this._handle.start(delay, 0);
      this._handle.domain = this.domain;
      this._handle.unref();
    }
    return this;
  }
  ref() {
    if (this._handle)
      this._handle.ref();
    return this;
  }
  close() {
    this._onTimeout = null;
    if (this._handle) {
      this._handle[kOnTimeout] = null;
      this._handle.close();
    } else {
      exports.unenroll(this);
    }
    return this;
  }
}

[Fishrock123]

No gain, more code change.

[benjamingr]

Well, it modernizes things a little and makes them more explicit. If we want to minimize change why not keep it const Timeout and do const Timeout = function Timeout - by naming the function expression you get the same trace.

[Fishrock123]

Why even assign it though? It's unnecessary.

Typically we have avoided modernization unless it meant performance increases or was part of some refactor that touched the code a lot anyways.

[benjamingr]

Fair enough - I'm sorry if all these questions annoy you :)

[ChALkeR]

LGTM

[MylesBorins]

@Fishrock123 can you confirm that this is safe and ready for v4?

[MylesBorins]

if this does land we should apply the lint fixes found in #5825

[Fishrock123]

@thealphanerd should be safe. It's a sorta-feature, but will only show up in logs I think. It's not even exported, so you can't do instanceof checks with it.

[MylesBorins]

@Fishrock123 I'm going to defer to your judgement here. Please feel free to send a backport PR or change the label