Node require watcher: exits the process when any require()'d files are changed.

require-watcher.coffee

# require-watcher.coffee
# Watches files that have been require()'d, and if they change, exits the
# current process, assuming that node-supervisor will then restart it.

fs = require 'fs'

# watch handler to exit the process on file changes:
watchFile = (filename) ->
    fs.watchFile filename, (oldStat, newStat) ->

        # we only care about files being modified; ignore events where the
        # last modified time hasn't changed.
        if newStat.mtime.getTime() is oldStat.mtime.getTime()
            return

        # otherwise, we have a file change! crash this sucker!
        console.log "File changed; exiting: #{filename}"
        process.exit 0

# wrapped require handlers to watch all required files:
for ext, handler of require.extensions
    require.extensions[ext] = (module, filename) ->
        watchFile filename
        handler module, filename