grunt-contrib-watch and grunt-notify duplicate alert deduplication boundary

Direct answer

Handle duplicate suppression in grunt-contrib-watch, not in grunt-notify. Configure the watch target's debounceDelay so rapid edits collapse into a single task run. grunt-notify has no change identity and fires once per completed task run, so it cannot deduplicate by itself. The interval option only sets polling cadence and does not group multiple changed files into one notification.

Confirmed facts

• grunt-notify fires after a task completes or when explicitly called; three task runs produce three alerts.
• grunt-contrib-watch owns the boundary between filesystem events and task execution.
• interval changes how often watch polls; it does not batch several changed files into one task run.
• debounceDelay resets a timer on each change and runs the task only after the burst quiets.
• interrupt controls whether a newer change cancels an in-flight run (true) or waits for it to finish (false).

Likely explanation

Rapid edits produce multiple filesystem events. Without debouncing, watch can start the same target task more than once per polling cycle or across cycles, and each completion triggers grunt-notify. A short interval raises CPU usage without suppressing duplicates; a long interval only delays them.

Configuration steps

1. Confirm installed versions: npm ls grunt-contrib-watch grunt-notify. Option names such as debounceDelay and interrupt are version-sensitive.
2. In your Gruntfile, set the watch target to debounce changes:

watch: {
  styles: {
    files: ['src/**/*.scss'],
    tasks: ['sass', 'notify:build'],
    options: {
      interval: 500,
      debounceDelay: 250,
      interrupt: true,
      spawn: false
    }
  }
}

1. Keep interval at a reasonable polling cadence; use debounceDelay for burst collapsing.
2. If multiple watch targets notify for the same edit, consolidate related globs into one target or make the task idempotent, because grunt-notify still fires once per target task completion.
3. To reduce noise without deduplicating, disable notify for noisy tasks or notify only on failure.

Verification

1. Run grunt watch and touch three files in one target within 200 ms: touch src/a.scss src/b.scss src/c.scss.
2. Compare OS notification count against watch task-run log lines; after debouncing they should match one alert per burst.
3. Hold debounceDelay fixed and change only interval; if duplicates remain, interval is not the deduplication boundary.

Missing diagnostic

Do duplicates appear when multiple files in one target change in a single burst, or when the same target retriggers after a previous run finishes? The first needs debounce or target consolidation; the second needs task-run policy such as interrupt.

Assumption: your installed grunt-contrib-watch supports debounceDelay and interrupt. Changing spawn alters process isolation and task-completion timing; test it with interrupt before relying on it to reduce duplicates.