From 47bc4046c57c7bdd10e7f20c2463fd447f505750 Mon Sep 17 00:00:00 2001
From: Patrik Oldsberg <poldsberg@gmail.com>
Date: Sun, 28 Jul 2024 21:24:03 +0200
Subject: [PATCH] frontend-plugin-api: add initial support for v2 extensions
 for blueprints

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
---
 .changeset/dry-squids-tap.md                  |   8 +-
 packages/frontend-plugin-api/api-report.md    | 143 +++++++++++-------
 .../src/extensions/IconBundleBlueprint.ts     |   8 +-
 .../src/wiring/createExtension.ts             |  38 +++--
 .../wiring/createExtensionBlueprint.test.tsx  |  54 ++-----
 .../src/wiring/createExtensionBlueprint.ts    | 137 ++++++++++++-----
 .../src/wiring/createExtensionDataRef.ts      |   6 +
 .../frontend-plugin-api/src/wiring/index.ts   |   1 +
 8 files changed, 235 insertions(+), 160 deletions(-)

diff --git a/.changeset/dry-squids-tap.md b/.changeset/dry-squids-tap.md
index 613ec4b7cb..0a95332eed 100644
--- a/.changeset/dry-squids-tap.md
+++ b/.changeset/dry-squids-tap.md
@@ -11,13 +11,9 @@ This allows the creation of extension instances with the following pattern:
 const EntityCardBlueprint = createExtensionBlueprint({
   kind: 'entity-card',
   attachTo: { id: 'test', input: 'default' },
-  output: {
-    element: coreExtensionData.reactElement,
-  },
+  output: [coreExtensionData.reactElement],
   factory(params: { text: string }) {
-    return {
-      element: <h1>{params.text}</h1>,
-    };
+    return [coreExtensionData.reactElement(<h1>{params.text}</h1>)];
   },
 });
 
diff --git a/packages/frontend-plugin-api/api-report.md b/packages/frontend-plugin-api/api-report.md
index 96c7675c0d..d37f0a3a56 100644
--- a/packages/frontend-plugin-api/api-report.md
+++ b/packages/frontend-plugin-api/api-report.md
@@ -593,24 +593,38 @@ export function createExtension<
 // @public
 export function createExtensionBlueprint<
   TParams,
-  TInputs extends AnyExtensionInputMap,
-  TOutput extends AnyExtensionDataMap,
+  UOutput extends AnyExtensionDataRef,
+  TInputs extends {
+    [inputName in string]: ExtensionInput<
+      AnyExtensionDataRef,
+      {
+        optional: boolean;
+        singleton: boolean;
+      }
+    >;
+  },
+  UExtraOutput extends AnyExtensionDataRef,
   TConfigSchema extends {
     [key in string]: (zImpl: typeof z) => z.ZodType;
   },
-  TDataRefs extends AnyExtensionDataMap = never,
+  UFactoryOutput extends ExtensionDataValue<any, any>,
+  TDataRefs extends {
+    [name in string]: AnyExtensionDataRef;
+  } = never,
 >(
   options: CreateExtensionBlueprintOptions<
     TParams,
+    UOutput,
     TInputs,
-    TOutput,
     TConfigSchema,
+    UFactoryOutput,
     TDataRefs
   >,
 ): ExtensionBlueprint<
   TParams,
+  UOutput,
   TInputs,
-  TOutput,
+  UExtraOutput,
   string extends keyof TConfigSchema
     ? {}
     : {
@@ -627,29 +641,38 @@ export function createExtensionBlueprint<
 >;
 
 // @public (undocumented)
-export interface CreateExtensionBlueprintOptions<
+export type CreateExtensionBlueprintOptions<
   TParams,
-  TInputs extends AnyExtensionInputMap,
-  TOutput extends AnyExtensionDataMap,
+  UOutput extends AnyExtensionDataRef,
+  TInputs extends {
+    [inputName in string]: ExtensionInput<
+      AnyExtensionDataRef,
+      {
+        optional: boolean;
+        singleton: boolean;
+      }
+    >;
+  },
   TConfigSchema extends {
     [key in string]: (zImpl: typeof z) => z.ZodType;
   },
-  TDataRefs extends AnyExtensionDataMap,
-> {
-  // (undocumented)
+  UFactoryOutput extends ExtensionDataValue<any, any>,
+  TDataRefs extends {
+    [name in string]: AnyExtensionDataRef;
+  },
+> = {
+  kind: string;
+  namespace?: string;
   attachTo: {
     id: string;
     input: string;
   };
-  // (undocumented)
+  disabled?: boolean;
+  inputs?: TInputs;
+  output: Array<UOutput>;
   config?: {
     schema: TConfigSchema;
   };
-  // (undocumented)
-  dataRefs?: TDataRefs;
-  // (undocumented)
-  disabled?: boolean;
-  // (undocumented)
   factory(
     params: TParams,
     context: {
@@ -659,16 +682,9 @@ export interface CreateExtensionBlueprintOptions<
       };
       inputs: Expand<ResolvedExtensionInputs<TInputs>>;
     },
-  ): Expand<ExtensionDataValues<TOutput>>;
-  // (undocumented)
-  inputs?: TInputs;
-  // (undocumented)
-  kind: string;
-  // (undocumented)
-  namespace?: string;
-  // (undocumented)
-  output: TOutput;
-}
+  ): Iterable<UFactoryOutput>;
+  dataRefs?: TDataRefs;
+} & VerifyExtensionFactoryOutput<UOutput, UFactoryOutput>;
 
 // @public @deprecated (undocumented)
 export function createExtensionDataRef<TData>(
@@ -769,22 +785,7 @@ export type CreateExtensionOptions<
           });
     inputs: Expand<ResolvedExtensionInputs<TInputs>>;
   }): Iterable<UFactoryOutput>;
-} & ((
-  UOutput extends any
-    ? UOutput['config']['optional'] extends true
-      ? never
-      : UOutput['id']
-    : never
-) extends infer IRequiredOutputIds
-  ? [IRequiredOutputIds] extends [UFactoryOutput['id']]
-    ? {}
-    : {
-        'Error: The extension factory is missing the following outputs': Exclude<
-          IRequiredOutputIds,
-          UFactoryOutput['id']
-        >;
-      }
-  : never);
+} & VerifyExtensionFactoryOutput<UOutput, UFactoryOutput>;
 
 // @public (undocumented)
 export function createExtensionOverrides(
@@ -1081,15 +1082,26 @@ export interface Extension<TConfig, TConfigInput = TConfig> {
 // @public (undocumented)
 export interface ExtensionBlueprint<
   TParams,
-  TInputs extends AnyExtensionInputMap,
-  TOutput extends AnyExtensionDataMap,
+  UOutput extends AnyExtensionDataRef,
+  TInputs extends {
+    [inputName in string]: ExtensionInput<
+      AnyExtensionDataRef,
+      {
+        optional: boolean;
+        singleton: boolean;
+      }
+    >;
+  },
+  UExtraOutput extends AnyExtensionDataRef,
   TConfig extends {
     [key in string]: unknown;
   },
   TConfigInput extends {
     [key in string]: unknown;
   },
-  TDataRefs extends AnyExtensionDataMap,
+  TDataRefs extends {
+    [name in string]: AnyExtensionDataRef;
+  },
 > {
   // (undocumented)
   dataRefs: TDataRefs;
@@ -1097,6 +1109,7 @@ export interface ExtensionBlueprint<
     TExtensionConfigSchema extends {
       [key in string]: (zImpl: typeof z) => z.ZodType;
     },
+    UFactoryOutput extends ExtensionDataValue<any, any>,
   >(
     args: {
       namespace?: string;
@@ -1107,7 +1120,7 @@ export interface ExtensionBlueprint<
       };
       disabled?: boolean;
       inputs?: TInputs;
-      output?: TOutput;
+      output?: Array<UExtraOutput>;
       config?: {
         schema: TExtensionConfigSchema & {
           [KName in keyof TConfig]?: `Error: Config key '${KName &
@@ -1115,7 +1128,7 @@ export interface ExtensionBlueprint<
         };
       };
     } & (
-      | {
+      | ({
           factory(
             originalFactory: (
               params: TParams,
@@ -1123,7 +1136,7 @@ export interface ExtensionBlueprint<
                 config?: TConfig;
                 inputs?: Expand<ResolvedExtensionInputs<TInputs>>;
               },
-            ) => Expand<ExtensionDataValues<TOutput>>,
+            ) => Iterable<ExtensionDataRefToValue<UOutput>>,
             context: {
               node: AppNode;
               config: TConfig & {
@@ -1133,8 +1146,11 @@ export interface ExtensionBlueprint<
               };
               inputs: Expand<ResolvedExtensionInputs<TInputs>>;
             },
-          ): Expand<ExtensionDataValues<TOutput>>;
-        }
+          ): Iterable<UFactoryOutput>;
+        } & VerifyExtensionFactoryOutput<
+          UOutput & UExtraOutput,
+          UFactoryOutput
+        >)
       | {
           params: TParams;
         }
@@ -1196,6 +1212,12 @@ export type ExtensionDataRef<
   readonly config: TConfig;
 };
 
+// @public (undocumented)
+export type ExtensionDataRefToValue<TDataRef extends AnyExtensionDataRef> =
+  TDataRef extends ExtensionDataRef<infer IData, infer IId, any>
+    ? ExtensionDataValue<IData, IId>
+    : never;
+
 // @public (undocumented)
 export type ExtensionDataValue<TData, TId extends string> = {
   readonly $$type: '@backstage/ExtensionDataValue';
@@ -1323,16 +1345,23 @@ export const IconBundleBlueprint: ExtensionBlueprint<
       [x: string]: IconComponent;
     };
   },
-  AnyExtensionInputMap,
+  ConfigurableExtensionDataRef<
+    {
+      [x: string]: IconComponent;
+    },
+    'core.icons',
+    {}
+  >,
   {
-    icons: ConfigurableExtensionDataRef<
+    [x: string]: ExtensionInput<
+      AnyExtensionDataRef,
       {
-        [x: string]: IconComponent;
-      },
-      'core.icons',
-      {}
+        optional: boolean;
+        singleton: boolean;
+      }
     >;
   },
+  AnyExtensionDataRef,
   {
     icons: string;
     test: string;
diff --git a/packages/frontend-plugin-api/src/extensions/IconBundleBlueprint.ts b/packages/frontend-plugin-api/src/extensions/IconBundleBlueprint.ts
index 438da09b4a..deeabdb44c 100644
--- a/packages/frontend-plugin-api/src/extensions/IconBundleBlueprint.ts
+++ b/packages/frontend-plugin-api/src/extensions/IconBundleBlueprint.ts
@@ -25,16 +25,16 @@ export const IconBundleBlueprint = createExtensionBlueprint({
   kind: 'icon-bundle',
   namespace: 'app',
   attachTo: { id: 'app', input: 'icons' },
-  output: {
-    icons: iconsDataRef,
-  },
+  output: [iconsDataRef],
   config: {
     schema: {
       icons: z => z.string().default('blob'),
       test: z => z.string(),
     },
   },
-  factory: (params: { icons: { [key in string]: IconComponent } }) => params,
+  factory: (params: { icons: { [key in string]: IconComponent } }) => [
+    iconsDataRef(params.icons),
+  ],
   dataRefs: {
     icons: iconsDataRef,
   },
diff --git a/packages/frontend-plugin-api/src/wiring/createExtension.ts b/packages/frontend-plugin-api/src/wiring/createExtension.ts
index 4034ef7238..4d31982ed3 100644
--- a/packages/frontend-plugin-api/src/wiring/createExtension.ts
+++ b/packages/frontend-plugin-api/src/wiring/createExtension.ts
@@ -145,6 +145,27 @@ export interface LegacyCreateExtensionOptions<
   }): Expand<ExtensionDataValues<TOutput>>;
 }
 
+/** @ignore */
+export type VerifyExtensionFactoryOutput<
+  UDeclaredOutput extends AnyExtensionDataRef,
+  UFactoryOutput extends ExtensionDataValue<any, any>,
+> = (
+  UDeclaredOutput extends any
+    ? UDeclaredOutput['config']['optional'] extends true
+      ? never
+      : UDeclaredOutput['id']
+    : never
+) extends infer IRequiredOutputIds
+  ? [IRequiredOutputIds] extends [UFactoryOutput['id']]
+    ? {}
+    : {
+        'Error: The extension factory is missing the following outputs': Exclude<
+          IRequiredOutputIds,
+          UFactoryOutput['id']
+        >;
+      }
+  : never;
+
 /** @public */
 export type CreateExtensionOptions<
   UOutput extends AnyExtensionDataRef,
@@ -183,22 +204,7 @@ export type CreateExtensionOptions<
           });
     inputs: Expand<ResolvedExtensionInputs<TInputs>>;
   }): Iterable<UFactoryOutput>;
-} & ((
-  UOutput extends any
-    ? UOutput['config']['optional'] extends true
-      ? never
-      : UOutput['id']
-    : never
-) extends infer IRequiredOutputIds
-  ? [IRequiredOutputIds] extends [UFactoryOutput['id']]
-    ? {}
-    : {
-        'Error: The extension factory is missing the following outputs': Exclude<
-          IRequiredOutputIds,
-          UFactoryOutput['id']
-        >;
-      }
-  : never);
+} & VerifyExtensionFactoryOutput<UOutput, UFactoryOutput>;
 
 /** @public */
 export interface ExtensionDefinition<TConfig, TConfigInput = TConfig> {
diff --git a/packages/frontend-plugin-api/src/wiring/createExtensionBlueprint.test.tsx b/packages/frontend-plugin-api/src/wiring/createExtensionBlueprint.test.tsx
index e4cb9e26f1..8b364f33c1 100644
--- a/packages/frontend-plugin-api/src/wiring/createExtensionBlueprint.test.tsx
+++ b/packages/frontend-plugin-api/src/wiring/createExtensionBlueprint.test.tsx
@@ -27,13 +27,9 @@ describe('createExtensionBlueprint', () => {
     const TestExtensionBlueprint = createExtensionBlueprint({
       kind: 'test-extension',
       attachTo: { id: 'test', input: 'default' },
-      output: {
-        element: coreExtensionData.reactElement,
-      },
+      output: [coreExtensionData.reactElement],
       factory(params: { text: string }) {
-        return {
-          element: <h1>{params.text}</h1>,
-        };
+        return [coreExtensionData.reactElement(<h1>{params.text}</h1>)];
       },
     });
 
@@ -56,12 +52,10 @@ describe('createExtensionBlueprint', () => {
       kind: 'test-extension',
       name: 'my-extension',
       namespace: undefined,
-      output: {
-        element: coreExtensionData.reactElement,
-      },
+      output: [coreExtensionData.reactElement],
       factory: expect.any(Function),
       toString: expect.any(Function),
-      version: 'v1',
+      version: 'v2',
     });
 
     const { container } = createExtensionTester(extension).render();
@@ -72,13 +66,9 @@ describe('createExtensionBlueprint', () => {
     const TestExtensionBlueprint = createExtensionBlueprint({
       kind: 'test-extension',
       attachTo: { id: 'test', input: 'default' },
-      output: {
-        element: coreExtensionData.reactElement,
-      },
+      output: [coreExtensionData.reactElement],
       factory(params: { text: string }) {
-        return {
-          element: <h1>{params.text}</h1>,
-        };
+        return [coreExtensionData.reactElement(<h1>{params.text}</h1>)];
       },
     });
 
@@ -103,16 +93,12 @@ describe('createExtensionBlueprint', () => {
     const TestExtensionBlueprint = createExtensionBlueprint({
       kind: 'test-extension',
       attachTo: { id: 'test', input: 'default' },
-      output: {
-        element: coreExtensionData.reactElement,
-      },
+      output: [coreExtensionData.reactElement],
       dataRefs: {
         data: dataRef,
       },
       factory(params: { text: string }) {
-        return {
-          element: <h1>{params.text}</h1>,
-        };
+        return [coreExtensionData.reactElement(<h1>{params.text}</h1>)];
       },
     });
 
@@ -125,9 +111,7 @@ describe('createExtensionBlueprint', () => {
     const TestExtensionBlueprint = createExtensionBlueprint({
       kind: 'test-extension',
       attachTo: { id: 'test', input: 'default' },
-      output: {
-        element: coreExtensionData.reactElement,
-      },
+      output: [coreExtensionData.reactElement],
       config: {
         schema: {
           text: z => z.string(),
@@ -142,9 +126,7 @@ describe('createExtensionBlueprint', () => {
 
         expect(config.text).toBe('Hello, world!');
 
-        return {
-          element: <h1>{config.text}</h1>,
-        };
+        return [coreExtensionData.reactElement(<h1>{config.text}</h1>)];
       },
     });
 
@@ -188,18 +170,14 @@ describe('createExtensionBlueprint', () => {
     const TestExtensionBlueprint = createExtensionBlueprint({
       kind: 'test-extension',
       attachTo: { id: 'test', input: 'default' },
-      output: {
-        element: coreExtensionData.reactElement,
-      },
+      output: [coreExtensionData.reactElement],
       config: {
         schema: {
           text: z => z.string(),
         },
       },
       factory(params: { text: string }) {
-        return {
-          element: <div>{params.text}</div>,
-        };
+        return [coreExtensionData.reactElement(<div>{params.text}</div>)];
       },
     });
 
@@ -224,16 +202,12 @@ describe('createExtensionBlueprint', () => {
     const TestExtensionBlueprint = createExtensionBlueprint({
       kind: 'test-extension',
       attachTo: { id: 'test', input: 'default' },
-      output: {
-        element: coreExtensionData.reactElement,
-      },
+      output: [coreExtensionData.reactElement],
       factory(_, { config }) {
         // @ts-expect-error
         const b = config.something;
 
-        return {
-          element: <div />,
-        };
+        return [coreExtensionData.reactElement(<div />)];
       },
     });
 
diff --git a/packages/frontend-plugin-api/src/wiring/createExtensionBlueprint.ts b/packages/frontend-plugin-api/src/wiring/createExtensionBlueprint.ts
index 7393ca233e..b579cc207a 100644
--- a/packages/frontend-plugin-api/src/wiring/createExtensionBlueprint.ts
+++ b/packages/frontend-plugin-api/src/wiring/createExtensionBlueprint.ts
@@ -17,31 +17,42 @@
 import { AppNode } from '../apis';
 import { Expand } from '../types';
 import {
-  AnyExtensionDataMap,
-  AnyExtensionInputMap,
-  ExtensionDataValues,
+  CreateExtensionOptions,
   ExtensionDefinition,
   ResolvedExtensionInputs,
+  VerifyExtensionFactoryOutput,
   createExtension,
 } from './createExtension';
 import { z } from 'zod';
+import { ExtensionInput } from './createExtensionInput';
+import {
+  AnyExtensionDataRef,
+  ExtensionDataRefToValue,
+  ExtensionDataValue,
+} from './createExtensionDataRef';
 
 /**
  * @public
  */
-export interface CreateExtensionBlueprintOptions<
+export type CreateExtensionBlueprintOptions<
   TParams,
-  TInputs extends AnyExtensionInputMap,
-  TOutput extends AnyExtensionDataMap,
+  UOutput extends AnyExtensionDataRef,
+  TInputs extends {
+    [inputName in string]: ExtensionInput<
+      AnyExtensionDataRef,
+      { optional: boolean; singleton: boolean }
+    >;
+  },
   TConfigSchema extends { [key in string]: (zImpl: typeof z) => z.ZodType },
-  TDataRefs extends AnyExtensionDataMap,
-> {
+  UFactoryOutput extends ExtensionDataValue<any, any>,
+  TDataRefs extends { [name in string]: AnyExtensionDataRef },
+> = {
   kind: string;
   namespace?: string;
   attachTo: { id: string; input: string };
   disabled?: boolean;
   inputs?: TInputs;
-  output: TOutput;
+  output: Array<UOutput>;
   config?: {
     schema: TConfigSchema;
   };
@@ -54,21 +65,27 @@ export interface CreateExtensionBlueprintOptions<
       };
       inputs: Expand<ResolvedExtensionInputs<TInputs>>;
     },
-  ): Expand<ExtensionDataValues<TOutput>>;
+  ): Iterable<UFactoryOutput>;
 
   dataRefs?: TDataRefs;
-}
+} & VerifyExtensionFactoryOutput<UOutput, UFactoryOutput>;
 
 /**
  * @public
  */
 export interface ExtensionBlueprint<
   TParams,
-  TInputs extends AnyExtensionInputMap,
-  TOutput extends AnyExtensionDataMap,
+  UOutput extends AnyExtensionDataRef,
+  TInputs extends {
+    [inputName in string]: ExtensionInput<
+      AnyExtensionDataRef,
+      { optional: boolean; singleton: boolean }
+    >;
+  },
+  UExtraOutput extends AnyExtensionDataRef,
   TConfig extends { [key in string]: unknown },
   TConfigInput extends { [key in string]: unknown },
-  TDataRefs extends AnyExtensionDataMap,
+  TDataRefs extends { [name in string]: AnyExtensionDataRef },
 > {
   dataRefs: TDataRefs;
 
@@ -82,6 +99,7 @@ export interface ExtensionBlueprint<
     TExtensionConfigSchema extends {
       [key in string]: (zImpl: typeof z) => z.ZodType;
     },
+    UFactoryOutput extends ExtensionDataValue<any, any>,
   >(
     args: {
       namespace?: string;
@@ -89,7 +107,7 @@ export interface ExtensionBlueprint<
       attachTo?: { id: string; input: string };
       disabled?: boolean;
       inputs?: TInputs;
-      output?: TOutput;
+      output?: Array<UExtraOutput>;
       config?: {
         schema: TExtensionConfigSchema & {
           [KName in keyof TConfig]?: `Error: Config key '${KName &
@@ -97,7 +115,7 @@ export interface ExtensionBlueprint<
         };
       };
     } & (
-      | {
+      | ({
           factory(
             originalFactory: (
               params: TParams,
@@ -105,7 +123,7 @@ export interface ExtensionBlueprint<
                 config?: TConfig;
                 inputs?: Expand<ResolvedExtensionInputs<TInputs>>;
               },
-            ) => Expand<ExtensionDataValues<TOutput>>,
+            ) => Iterable<ExtensionDataRefToValue<UOutput>>,
             context: {
               node: AppNode;
               config: TConfig & {
@@ -115,8 +133,11 @@ export interface ExtensionBlueprint<
               };
               inputs: Expand<ResolvedExtensionInputs<TInputs>>;
             },
-          ): Expand<ExtensionDataValues<TOutput>>;
-        }
+          ): Iterable<UFactoryOutput>;
+        } & VerifyExtensionFactoryOutput<
+          UOutput & UExtraOutput,
+          UFactoryOutput
+        >)
       | {
           params: TParams;
         }
@@ -143,17 +164,24 @@ export interface ExtensionBlueprint<
  */
 class ExtensionBlueprintImpl<
   TParams,
-  TInputs extends AnyExtensionInputMap,
-  TOutput extends AnyExtensionDataMap,
+  UOutput extends AnyExtensionDataRef,
+  TInputs extends {
+    [inputName in string]: ExtensionInput<
+      AnyExtensionDataRef,
+      { optional: boolean; singleton: boolean }
+    >;
+  },
+  UExtraOutput extends AnyExtensionDataRef,
   TConfigSchema extends { [key in string]: (zImpl: typeof z) => z.ZodType },
-  TDataRefs extends AnyExtensionDataMap,
+  TDataRefs extends { [name in string]: AnyExtensionDataRef },
 > {
   constructor(
     private readonly options: CreateExtensionBlueprintOptions<
       TParams,
+      UOutput,
       TInputs,
-      TOutput,
       TConfigSchema,
+      any,
       TDataRefs
     >,
   ) {
@@ -166,13 +194,14 @@ class ExtensionBlueprintImpl<
     TExtensionConfigSchema extends {
       [key in string]: (zImpl: typeof z) => z.ZodType;
     },
+    UFactoryOutput extends ExtensionDataValue<any, any>,
   >(args: {
     namespace?: string;
     name?: string;
     attachTo?: { id: string; input: string };
     disabled?: boolean;
     inputs?: TInputs;
-    output?: TOutput;
+    output?: Array<UExtraOutput>;
     params?: TParams;
     config?: {
       schema: TExtensionConfigSchema;
@@ -188,7 +217,7 @@ class ExtensionBlueprintImpl<
           };
           inputs?: Expand<ResolvedExtensionInputs<TInputs>>;
         },
-      ) => Expand<ExtensionDataValues<TOutput>>,
+      ) => Iterable<ExtensionDataRefToValue<UOutput>>,
       context: {
         node: AppNode;
         config: {
@@ -200,7 +229,7 @@ class ExtensionBlueprintImpl<
         };
         inputs: Expand<ResolvedExtensionInputs<TInputs>>;
       },
-    ): Expand<ExtensionDataValues<TOutput>>;
+    ): Iterable<UFactoryOutput>;
   }): ExtensionDefinition<
     {
       [key in keyof TExtensionConfigSchema]: z.infer<
@@ -232,7 +261,7 @@ class ExtensionBlueprintImpl<
       attachTo: args.attachTo ?? this.options.attachTo,
       disabled: args.disabled ?? this.options.disabled,
       inputs: args.inputs ?? this.options.inputs,
-      output: args.output ?? this.options.output,
+      output: [...(args.output ?? []), ...this.options.output],
       config: Object.keys(schema).length === 0 ? undefined : { schema },
       factory: ({ node, config, inputs }) => {
         if (args.factory) {
@@ -247,12 +276,13 @@ class ExtensionBlueprintImpl<
                 };
                 inputs?: Expand<ResolvedExtensionInputs<TInputs>>;
               },
-            ) =>
-              this.options.factory(innerParams, {
+            ): Iterable<ExtensionDataRefToValue<UOutput>> => {
+              return this.options.factory(innerParams, {
                 node,
                 config: innerContext?.config ?? config,
                 inputs: innerContext?.inputs ?? inputs,
-              }),
+              });
+            },
             {
               node,
               config,
@@ -268,7 +298,30 @@ class ExtensionBlueprintImpl<
         }
         throw new Error('Either params or factory must be provided');
       },
-    });
+    } as CreateExtensionOptions<
+      UOutput,
+      TInputs,
+      {
+        [key in keyof TExtensionConfigSchema]: z.infer<
+          ReturnType<TExtensionConfigSchema[key]>
+        >;
+      } & {
+        [key in keyof TConfigSchema]: z.infer<ReturnType<TConfigSchema[key]>>;
+      },
+      z.input<
+        z.ZodObject<
+          {
+            [key in keyof TExtensionConfigSchema]: ReturnType<
+              TExtensionConfigSchema[key]
+            >;
+          } & {
+            [key in keyof TConfigSchema]: ReturnType<TConfigSchema[key]>;
+          }
+        >
+      >,
+      TConfigSchema,
+      UFactoryOutput
+    >);
   }
 }
 
@@ -280,22 +333,31 @@ class ExtensionBlueprintImpl<
  */
 export function createExtensionBlueprint<
   TParams,
-  TInputs extends AnyExtensionInputMap,
-  TOutput extends AnyExtensionDataMap,
+  UOutput extends AnyExtensionDataRef,
+  TInputs extends {
+    [inputName in string]: ExtensionInput<
+      AnyExtensionDataRef,
+      { optional: boolean; singleton: boolean }
+    >;
+  },
+  UExtraOutput extends AnyExtensionDataRef,
   TConfigSchema extends { [key in string]: (zImpl: typeof z) => z.ZodType },
-  TDataRefs extends AnyExtensionDataMap = never,
+  UFactoryOutput extends ExtensionDataValue<any, any>,
+  TDataRefs extends { [name in string]: AnyExtensionDataRef } = never,
 >(
   options: CreateExtensionBlueprintOptions<
     TParams,
+    UOutput,
     TInputs,
-    TOutput,
     TConfigSchema,
+    UFactoryOutput,
     TDataRefs
   >,
 ): ExtensionBlueprint<
   TParams,
+  UOutput,
   TInputs,
-  TOutput,
+  UExtraOutput,
   string extends keyof TConfigSchema
     ? {}
     : { [key in keyof TConfigSchema]: z.infer<ReturnType<TConfigSchema[key]>> },
@@ -310,8 +372,9 @@ export function createExtensionBlueprint<
 > {
   return new ExtensionBlueprintImpl(options) as ExtensionBlueprint<
     TParams,
+    UOutput,
     TInputs,
-    TOutput,
+    UExtraOutput,
     string extends keyof TConfigSchema
       ? {}
       : {
diff --git a/packages/frontend-plugin-api/src/wiring/createExtensionDataRef.ts b/packages/frontend-plugin-api/src/wiring/createExtensionDataRef.ts
index f4b348ae51..c77aa8c394 100644
--- a/packages/frontend-plugin-api/src/wiring/createExtensionDataRef.ts
+++ b/packages/frontend-plugin-api/src/wiring/createExtensionDataRef.ts
@@ -33,6 +33,12 @@ export type ExtensionDataRef<
   readonly config: TConfig;
 };
 
+/** @public */
+export type ExtensionDataRefToValue<TDataRef extends AnyExtensionDataRef> =
+  TDataRef extends ExtensionDataRef<infer IData, infer IId, any>
+    ? ExtensionDataValue<IData, IId>
+    : never;
+
 /** @public */
 export type AnyExtensionDataRef = ExtensionDataRef<
   unknown,
diff --git a/packages/frontend-plugin-api/src/wiring/index.ts b/packages/frontend-plugin-api/src/wiring/index.ts
index 4b99ba8ebc..a17dfedc16 100644
--- a/packages/frontend-plugin-api/src/wiring/index.ts
+++ b/packages/frontend-plugin-api/src/wiring/index.ts
@@ -36,6 +36,7 @@ export {
   createExtensionDataRef,
   type AnyExtensionDataRef,
   type ExtensionDataRef,
+  type ExtensionDataRefToValue,
   type ExtensionDataValue,
   type ConfigurableExtensionDataRef,
 } from './createExtensionDataRef';