Move LoaderFactory decorator to data-loader/ & use new metadata abstraction

Author: CarsonF

src/components/file/media/media-by-file-version.loader.ts

@@ -3,7 +3,7 @@ import {
   type DataLoaderStrategy,
 } from '@seedcompany/data-loader';
 import { type ID } from '~/common';
-import { LoaderFactory } from '~/core/resources';
+import { LoaderFactory } from '~/core/data-loader';
 import { type AnyMedia } from './media.dto';
 import { MediaRepository } from './media.repository';
 

src/components/file/media/media.loader.ts

@@ -1,6 +1,6 @@
 import { type DataLoaderStrategy } from '@seedcompany/data-loader';
 import { type ID } from '~/common';
-import { LoaderFactory } from '~/core/resources';
+import { LoaderFactory } from '~/core/data-loader';
 import { type AnyMedia, Media } from './media.dto';
 import { MediaRepository } from './media.repository';
 

src/core/data-loader/index.ts

@@ -6,6 +6,7 @@ export {
 } from '@seedcompany/data-loader';
 
 export * from './options.type';
+export { LoaderFactory } from './loader-factory.decorator';
 export * from './session-aware-loader.strategy';
 export * from './ordered-data-loader.strategy';
 export * from './single-item-loader.strategy';

src/core/data-loader/loader-factory.decorator.ts

@@ -0,0 +1,53 @@
+import { Injectable, Scope, type Type } from '@nestjs/common';
+import type { DataLoaderStrategy } from '@seedcompany/data-loader';
+import { createMetadataDecorator } from '@seedcompany/nest';
+import type { ValueOf } from 'type-fest';
+import type { Many } from '~/common';
+import { type ResourceMap } from '~/core/resources';
+import { ObjectViewAwareLoader } from './object-view-aware-loader.strategy';
+
+type SomeResource = ValueOf<ResourceMap>;
+
+type DataLoaderCtor = Type<DataLoaderStrategy<any, any>>;
+
+export interface LoaderOptions {
+  /**
+   * Whether the loader is aware of ObjectViews.
+   *
+   * This means the loader key needs to be in the shape of
+   * {@link import('../data-loader/object-view-aware-loader.strategy').Key Key}
+   *
+   * This defaults to true if the class extends ObjectViewAwareLoader.
+   */
+  objectViewAware?: boolean;
+}
+
+export const LoaderFactoryMetadata = createMetadataDecorator({
+  types: ['class'],
+  setter: (resource?: () => Many<SomeResource>, options?: LoaderOptions) => ({
+    resource,
+    ...options,
+  }),
+});
+
+/**
+ * Register this class as a DataLoader for the given resource(s)
+ *
+ * @param resource Connect this loader to this resource, so it can be accessed dynamically.
+ * @param options
+ */
+export const LoaderFactory =
+  (
+    resource?: () => Many<SomeResource>,
+    options?: LoaderOptions,
+  ): (<LoaderCtor extends DataLoaderCtor>(target: LoaderCtor) => void) =>
+  (target) => {
+    Injectable({ scope: Scope.REQUEST })(target);
+
+    LoaderFactoryMetadata(resource, {
+      ...options,
+      objectViewAware:
+        options?.objectViewAware ??
+        Object.getPrototypeOf(target) === ObjectViewAwareLoader,
+    })(target);
+  };

src/core/resources/index.ts

@@ -1,5 +1,4 @@
 export * from './resource-resolver.service';
-export { LoaderFactory } from './loader.registry';
 export * from './resource.loader';
 export * from './resources.host';
 export * from './resource-name.types';

src/core/resources/loader.registry.ts

@@ -2,61 +2,16 @@ import {
   Injectable,
   type OnModuleInit,
   Scope,
-  SetMetadata,
   type Type,
 } from '@nestjs/common';
 import { ModulesContainer } from '@nestjs/core';
 import { type DataLoaderStrategy } from '@seedcompany/data-loader';
-import type { ValueOf } from 'type-fest';
-import { many, type Many } from '~/common';
+import { many } from '~/common';
 import { type ResourceMap } from '~/core';
-import { ObjectViewAwareLoader } from '../data-loader';
-
-type SomeResource = ValueOf<ResourceMap>;
-
-const LOADER_OF_RESOURCE = Symbol('LOADER_OF_RESOURCE');
-
-interface MetadataShape extends LoaderOptions {
-  resource?: () => Many<SomeResource>;
-}
-
-interface LoaderOptions {
-  /**
-   * Whether the loader is aware of ObjectViews.
-   *
-   * This means the loader key needs to be in the shape of
-   * {@link import('../data-loader/object-view-aware-loader.strategy').Key Key}
-   *
-   * This defaults to true if the class extends ObjectViewAwareLoader.
-   */
-  objectViewAware?: boolean;
-}
-
-type DataLoaderCtor = Type<DataLoaderStrategy<any, any>>;
-
-/**
- * Register this class as a DataLoader for the given resource(s)
- *
- * @param resource Connect this loader to this resource, so it can be accessed dynamically.
- * @param options
- */
-export const LoaderFactory =
-  (
-    resource?: () => Many<SomeResource>,
-    options?: LoaderOptions,
-  ): (<LoaderCtor extends DataLoaderCtor>(target: LoaderCtor) => void) =>
-  (target) => {
-    Injectable({ scope: Scope.REQUEST })(target);
-
-    const metadata: MetadataShape = {
-      resource,
-      ...options,
-      objectViewAware:
-        options?.objectViewAware ??
-        Object.getPrototypeOf(target) === ObjectViewAwareLoader,
-    };
-    SetMetadata(LOADER_OF_RESOURCE, metadata)(target);
-  };
+import {
+  LoaderFactoryMetadata,
+  type LoaderOptions,
+} from '../data-loader/loader-factory.decorator';
 
 @Injectable()
 export class ResourceLoaderRegistry implements OnModuleInit {
@@ -75,10 +30,7 @@ export class ResourceLoaderRegistry implements OnModuleInit {
         if (!provider.metatype) {
           return [];
         }
-        const metadata = Reflect.getMetadata(
-          LOADER_OF_RESOURCE,
-          provider.metatype,
-        ) as MetadataShape | undefined;
+        const metadata = LoaderFactoryMetadata.get(provider.metatype as Type);
         return metadata ? { ...metadata, provider } : [];
       });
     for (const { resource, provider, ...options } of loaderFactories) {