backend-plugin-api: fix type inference of interface options

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

.changeset/itchy-schools-run.md

@@ -0,0 +1,5 @@
+---
+'@backstage/backend-plugin-api': patch
+---
+
+Allow interfaces to be used for inferred option types.

packages/backend-plugin-api/api-report.md

@@ -73,11 +73,7 @@ export const configServiceRef: ServiceRef<Config, 'root'>;
 
 // @public (undocumented)
 export function createBackendModule<
-  TOptions extends
-    | {
-        [name: string]: unknown;
-      }
-    | undefined = undefined,
+  TOptions extends object | undefined = undefined,
 >(
   config: BackendModuleConfig<TOptions>,
 ): undefined extends TOptions
@@ -86,14 +82,11 @@ export function createBackendModule<
 
 // @public (undocumented)
 export function createBackendPlugin<
-  TOptions extends
-    | {
-        [name: string]: unknown;
-      }
-    | undefined = undefined,
->(
-  config: BackendPluginConfig<TOptions>,
-): undefined extends TOptions
+  TOptions extends object | undefined = undefined,
+>(config: {
+  id: string;
+  register(reg: BackendRegistrationPoints, options: TOptions): void;
+}): undefined extends TOptions
   ? (options?: TOptions) => BackendFeature
   : (options: TOptions) => BackendFeature;
 
@@ -110,11 +103,7 @@ export function createServiceFactory<
   TDeps extends {
     [name in string]: ServiceRef<unknown>;
   },
-  TOpts extends
-    | {
-        [name in string]: unknown;
-      }
-    | undefined = undefined,
+  TOpts extends object | undefined = undefined,
 >(config: {
   service: ServiceRef<TService, TScope>;
   deps: TDeps;

packages/backend-plugin-api/src/services/system/types.test.ts

@@ -58,6 +58,8 @@ describe('createServiceFactory', () => {
     metaFactory({});
     metaFactory({ x: 1 });
     // @ts-expect-error
+    metaFactory({ x: 1, y: 2 });
+    // @ts-expect-error
     metaFactory(null);
     metaFactory(undefined);
     metaFactory();
@@ -80,10 +82,145 @@ describe('createServiceFactory', () => {
     metaFactory({});
     metaFactory({ x: 1 });
     // @ts-expect-error
+    metaFactory({ x: 1, y: 2 });
+    // @ts-expect-error
     metaFactory(null);
     // @ts-expect-error
     metaFactory(undefined);
     // @ts-expect-error
     metaFactory();
   });
+
+  it('should create a meta factory with optional options as interface', () => {
+    interface TestOptions {
+      x: number;
+    }
+    const ref = createServiceRef<string>({ id: 'x' });
+    const metaFactory = createServiceFactory({
+      service: ref,
+      deps: {},
+      async factory(_deps, _opts?: TestOptions) {
+        return async () => 'x';
+      },
+    });
+    expect(metaFactory).toEqual(expect.any(Function));
+
+    // @ts-expect-error
+    metaFactory('string');
+    // @ts-expect-error
+    metaFactory({});
+    metaFactory({ x: 1 });
+    // @ts-expect-error
+    metaFactory({ x: 1, y: 2 });
+    // @ts-expect-error
+    metaFactory(null);
+    metaFactory(undefined);
+    metaFactory();
+  });
+
+  it('should create a meta factory with required options as interface', () => {
+    interface TestOptions {
+      x: number;
+    }
+    const ref = createServiceRef<string>({ id: 'x' });
+    const metaFactory = createServiceFactory({
+      service: ref,
+      deps: {},
+      async factory(_deps, _opts: TestOptions) {
+        return async () => 'x';
+      },
+    });
+    expect(metaFactory).toEqual(expect.any(Function));
+
+    // @ts-expect-error
+    metaFactory('string');
+    // @ts-expect-error
+    metaFactory({});
+    metaFactory({ x: 1 });
+    // @ts-expect-error
+    metaFactory({ x: 1, y: 2 });
+    // @ts-expect-error
+    metaFactory(null);
+    // @ts-expect-error
+    metaFactory(undefined);
+    // @ts-expect-error
+    metaFactory();
+  });
+
+  it('should only allow objects as options', () => {
+    const ref = createServiceRef<string>({ id: 'x' });
+    const metaFactory = createServiceFactory({
+      service: ref,
+      deps: {},
+      // @ts-expect-error
+      async factory(_deps, _opts: string) {
+        return async () => 'x';
+      },
+    });
+    expect(metaFactory).toEqual(expect.any(Function));
+    createServiceFactory({
+      service: ref,
+      deps: {},
+      // @ts-expect-error
+      async factory(_deps, _opts: number) {
+        return async () => 'x';
+      },
+    });
+    createServiceFactory({
+      service: ref,
+      deps: {},
+      // @ts-expect-error
+      async factory(_deps, _opts: symbol) {
+        return async () => 'x';
+      },
+    });
+    createServiceFactory({
+      service: ref,
+      deps: {},
+      // @ts-expect-error
+      async factory(_deps, _opts: bigint) {
+        return async () => 'x';
+      },
+    });
+    createServiceFactory({
+      service: ref,
+      deps: {},
+      // @ts-expect-error
+      async factory(_deps, _opts: 'string') {
+        return async () => 'x';
+      },
+    });
+    createServiceFactory({
+      service: ref,
+      deps: {},
+      // @ts-expect-error
+      async factory(_deps, _opts: Array) {
+        return async () => 'x';
+      },
+    });
+    createServiceFactory({
+      service: ref,
+      deps: {},
+      // @ts-expect-error
+      async factory(_deps, _opts: Map) {
+        return async () => 'x';
+      },
+    });
+    createServiceFactory({
+      service: ref,
+      deps: {},
+      // @ts-expect-error
+      async factory(_deps, _opts: Set) {
+        return async () => 'x';
+      },
+    });
+    createServiceFactory({
+      service: ref,
+      deps: {},
+      // @ts-expect-error
+      async factory(_deps, _opts: null) {
+        return async () => 'x';
+      },
+    });
+  });
 });

packages/backend-plugin-api/src/services/system/types.ts

@@ -133,7 +133,7 @@ export function createServiceFactory<
   TScope extends 'root' | 'plugin',
   TImpl extends TService,
   TDeps extends { [name in string]: ServiceRef<unknown> },
-  TOpts extends { [name in string]: unknown } | undefined = undefined,
+  TOpts extends object | undefined = undefined,
 >(config: {
   service: ServiceRef<TService, TScope>;
   deps: TDeps;

packages/backend-plugin-api/src/wiring/factories.test.ts

@@ -68,6 +68,38 @@ describe('createBackendPlugin', () => {
     // @ts-expect-error
     expect(plugin({})).toBeDefined();
   });
+
+  it('should create a BackendPlugin with options as interface', () => {
+    interface TestOptions {
+      a: string;
+    }
+    const plugin = createBackendPlugin({
+      id: 'x',
+      register(_reg, _options: TestOptions) {},
+    });
+    expect(plugin).toBeDefined();
+    expect(plugin({ a: 'a' })).toBeDefined();
+    expect(plugin({ a: 'a' }).id).toBe('x');
+    // @ts-expect-error
+    expect(plugin()).toBeDefined();
+    // @ts-expect-error
+    expect(plugin({ b: 'b' })).toBeDefined();
+  });
+
+  it('should create plugins with optional options as interface', () => {
+    interface TestOptions {
+      a: string;
+    }
+    const plugin = createBackendPlugin({
+      id: 'x',
+      register(_reg, _options?: TestOptions) {},
+    });
+    expect(plugin).toBeDefined();
+    expect(plugin({ a: 'a' })).toBeDefined();
+    expect(plugin()).toBeDefined();
+    // @ts-expect-error
+    expect(plugin({ b: 'b' })).toBeDefined();
+  });
 });
 
 describe('createBackendModule', () => {
@@ -111,4 +143,38 @@ describe('createBackendModule', () => {
     // @ts-expect-error
     expect(mod({})).toBeDefined();
   });
+
+  it('should create a BackendModule as interface', () => {
+    interface TestOptions {
+      a: string;
+    }
+    const mod = createBackendModule({
+      pluginId: 'x',
+      moduleId: 'y',
+      register(_reg, _options: TestOptions) {},
+    });
+    expect(mod).toBeDefined();
+    expect(mod({ a: 'a' })).toBeDefined();
+    expect(mod({ a: 'a' }).id).toBe('x.y');
+    // @ts-expect-error
+    expect(mod()).toBeDefined();
+    // @ts-expect-error
+    expect(mod({ b: 'b' })).toBeDefined();
+  });
+
+  it('should create modules with optional options as interface', () => {
+    interface TestOptions {
+      a: string;
+    }
+    const mod = createBackendModule({
+      pluginId: 'x',
+      moduleId: 'y',
+      register(_reg, _options?: TestOptions) {},
+    });
+    expect(mod).toBeDefined();
+    expect(mod({ a: 'a' })).toBeDefined();
+    expect(mod()).toBeDefined();
+    // @ts-expect-error
+    expect(mod({ b: 'b' })).toBeDefined();
+  });
 });

packages/backend-plugin-api/src/wiring/factories.ts

@@ -44,10 +44,11 @@ export interface BackendPluginConfig<TOptions> {
 
 /** @public */
 export function createBackendPlugin<
-  TOptions extends { [name: string]: unknown } | undefined = undefined,
->(
-  config: BackendPluginConfig<TOptions>,
-): undefined extends TOptions
+  TOptions extends object | undefined = undefined,
+>(config: {
+  id: string;
+  register(reg: BackendRegistrationPoints, options: TOptions): void;
+}): undefined extends TOptions
   ? (options?: TOptions) => BackendFeature
   : (options: TOptions) => BackendFeature {
   return (options?: TOptions) => ({
@@ -70,7 +71,7 @@ export interface BackendModuleConfig<TOptions> {
 
 /** @public */
 export function createBackendModule<
-  TOptions extends { [name: string]: unknown } | undefined = undefined,
+  TOptions extends object | undefined = undefined,
 >(
   config: BackendModuleConfig<TOptions>,
 ): undefined extends TOptions