Simple macos-only file watcher (basic concept, not done)

watch.coffee

#!/usr/bin/env coffee

fs = require 'fs'
fp = require 'path'
EventEmitter = require 'events'

class Watcher extends EventEmitter
  constructor: (globs, cb) ->
    super()
    @watch globs, cb if globs?.length

  watch: (globs, cb) ->
    path = globs[0] # TODO: process all, not just first one
    @watchPath path, cb

  baseFilter: (base, cb) -> (type, path) ->
    if path.startsWith(base) and (path[base.length] or '/') is '/'
      type = fs.existsSync(path) and 'update' or 'remove'
      cb type, path

  watchPath: (path, cb) ->
    parent = fp.dirname path
    base = fp.basename path
    @fswatcher = fs.watch parent, recursive: true
      .on 'change', @baseFilter base, cb # TODO: debounce cb
    @

new Watcher ['app', 'vendor'], (type, path) -> console.log "[#{type}] #{path}"

### NOTE: Test as follows:

watch.coffee &
mkdir -p app/b/c/d/e
rm -rf app

###