Note from maintainers: Support for Coffeescript is deprecated and will be removed in Bokeh 2.0.
The other day, I asked about how to
Unless I am mistaken, you only need to access nth as an instance variable, by putting this. in front of it.
Edit: You also need to use the "fat arrow" => in your filter, so that this is properly bound (otherwise this is undefined in that context).
ticks.major = ticks.major.filter((element, index) => index % this.nth == 0)