How to filter copy files (Ionic 2 RC1)?

Ionic Framework ionic-v3
1

Hello!
I got a rule in watch.config.js:

{
      paths: [
        '{{SRC}}/app',
        '{{SRC}}/pages',
        '{{SRC}}/assets',
      ],
      callback: copyUpdate
    },

I try to apply options, to cancel copy file with .ts extention:

{
      paths: [
        '{{SRC}}/app',
        '{{SRC}}/pages',
        '{{SRC}}/assets',
      ],
      options: { ignored: /([a-zA-z].ts$)/, filter:  /([a-zA-z].ts$)/},
      callback: copyUpdate
    },

How to filter files with .ts extention?