Universal Analytics (analytics.js) Ignoring own traffic

Question

From google's documentation:

The analytics.js snippet is part of Universal Analytics, which is currently in public beta. New users should use analytics.js. Existing ga.js users should create a new web property for analytics.js and dual tag their site. It is perfectly safe to include both ga.js and analytics.js snippets on the same page.

However, I can't seem to find a way to set up a filter to exclude my own traffic with a cookie. There is this for ga.js, but as far as I can tell there is no way to set a custom variable with analytics.js, and I get get a custom dimension to work.

Edit: What I've done thus far:

1. Set up a custom dimension called 'ignore' in GA via the UI
2. Created a filter specifying the custom dimension from step 1
3. called ga('set', 'dimension1', 1); my website

traffic is not ignored

Answer 1

Why not just set your own cookie and check against it using the opt out var?

window['ga-disable-UA-XXXX-Y'] = true;