Adjust ResourcesHost.getByEdgeDB to give strict resource types from strict keys

Author: CarsonF

src/common/resource.dto.ts

@@ -249,9 +249,7 @@ export class EnhancedResource<T extends ResourceShape<any>> {
     return type as any;
   }
 
-  get dbFQN(): ResourceShape<any> extends T
-    ? string
-    : DBType<T>['__element__']['__name__'] {
+  get dbFQN(): ResourceShape<any> extends T ? string : DBName<DBType<T>> {
     return this.db.__element__.__name__ as any;
   }
 
@@ -307,6 +305,8 @@ export type DBType<TResourceStatic extends ResourceShape<any>> =
       : never
     : never;
 
+export type DBName<T extends $.TypeSet> = T['__element__']['__name__'];
+
 export type MaybeUnsecuredInstance<TResourceStatic extends ResourceShape<any>> =
   MaybeSecured<InstanceType<TResourceStatic>>;
 

src/core/resources/resources.host.ts

@@ -3,14 +3,15 @@ import { GraphQLSchemaHost } from '@nestjs/graphql';
 import { CachedByArg, mapKeys } from '@seedcompany/common';
 import { isObjectType } from 'graphql';
 import { mapValues } from 'lodash';
-import { LiteralUnion, ValueOf } from 'type-fest';
+import { ConditionalKeys, LiteralUnion, ValueOf } from 'type-fest';
 import {
+  DBName,
   EnhancedResource,
   InvalidIdForTypeException,
   ResourceShape,
   ServerException,
 } from '~/common';
-import { ResourceMap } from './map';
+import { ResourceDBMap, ResourceMap } from './map';
 import { __privateDontUseThis } from './resource-map-holder';
 
 export type EnhancedResourceMap = {
@@ -24,6 +25,10 @@ export type ResourceLike =
   | EnhancedResource<any>
   | LooseResourceName;
 
+type ResourceNameFromDBName<K extends DBName<ValueOf<ResourceDBMap>>> =
+  // eslint-disable-next-line @typescript-eslint/naming-convention
+  ConditionalKeys<ResourceDBMap, { __element__: { __name__: K } }>;
+
 @Injectable()
 export class ResourcesHost {
   constructor(private readonly gqlSchema: GraphQLSchemaHost) {}
@@ -65,7 +70,14 @@ export class ResourcesHost {
     return this.getByName(name as any);
   }
 
-  getByEdgeDB(name: string): EnhancedResource<ValueOf<ResourceMap>> {
+  getByEdgeDB<K extends keyof ResourceMap>(
+    name: K,
+  ): EnhancedResource<ValueOf<Pick<ResourceMap, K>>>;
+  getByEdgeDB<K extends DBName<ValueOf<ResourceDBMap>>>(
+    name: K,
+  ): EnhancedResource<ValueOf<Pick<ResourceMap, ResourceNameFromDBName<K>>>>;
+  getByEdgeDB(name: string): EnhancedResource<any>;
+  getByEdgeDB(name: string) {
     const fqnMap = this.edgeDBFQNMap();
     const resByFQN = fqnMap.get(
       name.includes('::') ? name : `default::${name}`,