tkellen/rake-pipeline-web-filters — comment on commit c0f5992fccd2f47f1846930ce7c157c8333bf13b
File: lib/rake-pipeline-web-filters/handlebars_filter.rb line 46
By dudleyf:

This filter depends on json for string escaping, so it needs to declare that as a dependency. You can look at one of the other filters like the [LessFilter](https://github.com/wycats/rake-pipeline-web-filters/blob/master/lib/rake-pipeline-web-filters/less_filter.rb) to see how it's done, but basically you need to include the `FilterWithDependencies` module and define an `external_dependencies` method.