# Additional information on Legacy frontend The legacy bundle is only used from Rails to add functionality to specific parts of the application. ## Loading and bootstrapping the legacy AngularJS frontend To bootstrap the AngularJS frontend from Rails, use the `activate_angular_js` helper block: ```html <%= activate_angular_js do %>

Something rendered from Rails ...

<% end %> ``` The legacy frontend with AngularJS can be bootstrapped _with_ content contained within. This is not possible in Angular, since the root component needs to be empty (or will be emptied during bootstrap). ## Passing information and configuration from Rails to Angular There are three ways of passing information from Rails to `AngularJS`: 1. Using tag attributes written directly to the DOM by the rendering process of Rails as in the example before. 2. Using the `gon` gem This is included by all layouts in ``: ```js <%= nonced_javascript_tag do %> <%= include_gon(need_tag: false) -%> <% end %> ``` `gon` will provide arbitrary settings from Rails to all JavaScript functionality, including `AngularJS`. In an `angular` context a `ConfigurationService` is provided for picking up the settings.