Harlem uses a combination of extensions and plugins to extend core functionality. Although extensions and plugins may appear similar, they serve different purposes. Here is a brief summary on the difference between extensions and plugins:

  • Extensions: extensions are registered per-store. They have deep integration with how the store is created, managed and typed.
  • Plugins: plugins are registered once globally. They are useful for high-level management of all stores which is why the devtools plugin is a good use-case for a plugin.

Official Extensions

  • Action (@harlem/extension-action) - Extends a store to support cancellable async actions.
  • Compose (@harlem/extension-compose) - Extends a store to to add simple read/write convenience methods.
  • History (Preview) (@harlem/extension-history) - Extends a store to support undo and redo capabilities.
  • Lazy (@harlem/extension-lazy) - Extends a store to support lazy async getters.
  • Reset (@harlem/extension-reset) - Extends a store to support resetting a store back to it's original state.
  • Snapshot (@harlem/extension-snapshot) - Extends a store to support taking snapshots of state and applying it at a later stage.
  • Storage (@harlem/extension-storage) - Extends a store to support synchronising state to/from localStorage or sessionStorage.
  • Trace (@harlem/extension-trace) - Extends a store to support tracing granular changes to state during mutations. Useful for auditing during development.
  • Transaction (@harlem/extension-transaction) - Extends a store to support rolling back multiple mutations if one fails.

Official Plugins

  • Devtools (@harlem/plugin-devtools) - The devtools plugin adds Vue devtools integration with your stores to show updates to your state in realtime.
  • SSR (@harlem/plugin-ssr) - The SSR plugin enables support for using Harlem stores in a server-side rendered application.