Need a nicer way of building plugins by assembling others.

[jonapgar-groupby]

Consider this "AuthPlugin" I've made here:

const authPluginFactory = (
  options: ReturnType<typeof buildAuthConfig>,
  prisma: PrismaClient
): Plugin<Pick<Context, 'agent'>> => ({
  onPluginInit({ addPlugin }) {
    // addPlugin should not require the added plugin to satisfy the context, but it does :shrug:
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    addPlugin(useAuth0(options) as Plugin<any>);
    addPlugin(useExtendContext(createAgentContextExtender(prisma)));
  },
});

Now I know I could have just done this:

plugins:[
  useAuth0(options),
  useExtendContext(createAgentContextExtender(prisma)
],

But I have ioc scenarios (e.g. testing) where I don't want to "useAuth0" at all, and I want my AuthPlugin provider to deal with all of that.

The above solution with callingaddPlugin multiple times works but as you can see I have to assert Plugin<any>, as addPlugin expects that I'm passing a Plugin that satisfies the PluginContext of the plugin that I'm actually creating.

It would be great if I could just call a method, something like this...

const combinePlugins<T1, T2, T3>(Plugin<T1>, Plugin<T2>, Plugin<T3>): Plugin<T1 & T2 & T3> = (...

Though maybe this doesn't make a lot of sense either.

The whole idea of PluginContext is kinda confusing to me. It seems like this type is doing double-duty and in some places is implying that the Plugin will extend the context with these fields, and other places it is implying "the context already has these fields".

The AfterContextBuildingEventPayload shows this strange duality.

/**
 * The payload forwarded to the afterContextBuilding hook.
 */
export type AfterContextBuildingEventPayload<ContextType> = {
  /**
   * The current context object.
   */
  context: ContextType;
  /**
   * Extend the context object with a partial.
   */
  extendContext: (contextExtension: Partial<ContextType>) => void;
};

[jonapgar-groupby]

I guess ideally the plugins array in envelop would enforce that the in and out context for each plugin. Plugins could require that a previous plugin as added some field to the context, and they can decide to extend/remove that field in their own implementation.

[n1ru4l]

Related #1566