Merge branch '293928-licensed-feature-flag-docs' into 'master'

Add docs for push_licensed_feature

See merge request gitlab-org/gitlab!58601

doc/development/ee_features.md

@@ -23,6 +23,8 @@ when no license is active. So EE features always should be guarded by
 `project.feature_available?` or `group.feature_available?` (or
 `License.feature_available?` if it is a system-wide feature).
 
+Frontend features should be guarded by pushing a flag from the backend by [using `push_licensed_feature`](licensed_feature_availability.md#restricting-frontend-features), and checked using `this.glFeatures.someFeature` in the frontend.
+
 CE specs should remain untouched as much as possible and extra specs
 should be added for EE. Licensed features can be stubbed using the
 spec helper `stub_licensed_features` in `EE::LicenseHelpers`.

doc/development/feature_flags/index.md

@@ -292,8 +292,7 @@ end
 
 ### Frontend
 
-Use the `push_frontend_feature_flag` method for frontend code, which is
-available to all controllers that inherit from `ApplicationController`. You can use
+Use the `push_frontend_feature_flag` method which is available to all controllers that inherit from `ApplicationController`. You can use
 this method to expose the state of a feature flag, for example:
 
 ```ruby

doc/development/licensed_feature_availability.md

@@ -41,3 +41,16 @@ the instance license.
 ```ruby
 License.feature_available?(:feature_symbol)
 ```
+
+## Restricting frontend features
+
+To restrict frontend features based on the license, use `push_licensed_feature`.
+The frontend can then access this via `this.glFeatures`:
+
+```ruby
+before_action do
+  push_licensed_feature(:feature_symbol)
+  # or by project/namespace
+  push_licensed_feature(:feature_symbol, project)
+end
+```