ui-plugin

API for composable 3rd party UI plugins

Goal

Enable a system of user interface plugins that meets the following criteria:

• Plugins are authered, compiled and deployed independently, by anyone under any repository.
• Plugins can also be authored locally, sharing modules and compilation with the host project.
• Plugins can be installed at run time. This includes download from an external repository like npm.
• Plugins can be enabled and disabled at run time, including newly installed ones. No restart of the host app required.
• Plugins can manage visual components, app state, or both.
• Plugins can emit events that other plugins can subscribe to.
• Plugins expose public methods that other plugins can call synchronously.
• Each plugin has read-write access to own its state.
• Plugin state is private. State can be made available to other plugins though methods.
• Plugins can define render slots that other plugins can plug into. More plugins can take up the same slot and can choose to compose or override each other.
• Render slots derive their inputs from plugin state and method APIs, and update automatically whenever the state of a relevant plugin changes.
• Renders slots are free to manage their own private state that isn't accessible at plugin level.
• Plugin API is type-friendly.
• Plugins can share common libraries (eg. React) by configuring the host app to attach those libraries to the global namespace and configuring the plugin build to map related imports to the global namespace.

Strategy

Use the global namespace to connect plugins from different script files. Expose declarative APIs for defining and registering plugins that abstracts the global namespace.

Design

• Registered plugins are enabled by default. In the user land, this indirectly leads to using a disabled plugin list to configure the enabled state of installed plugins (ie. a deny list).
• Enabling a plugin at run-time will reload all plugins. Other plugins' onLoad handlers might perform actions that are relevant to the newly enabled plugin. This leads to a deterministic collective plugin outcome, regardless of when a plugin is enabled. But while plugin execution resets, previous state is preserved.