feat: add init function to apiClientFactory params

Author: WojtekTheWebDev

Diff for: .changeset/wet-cups-bathe.md

@@ -0,0 +1,28 @@
+---
+"@vue-storefront/middleware": minor
+---
+
+[ADDED] an `init` function to the `apiClientFactory` parameters. It reduces boilerplate code and helps with type suggestions of the input and output of the function.
+
+```diff
+- const init = (config) => {
+-   return {
+-     ...config,
+-     client: buildClient(config),
+-   }
+- }
+
+- const { createApiClient } = apiClientFactory({
++ const { createApiClient, init } = apiClientFactory({
+  onCreate: (config) => config,
+  api: { ... }
++  init: (config) => {
++    return {
++      ...config,
++      client: buildClient(config),
++    }
++  },
+})
+
+export const { createApiClient, init };
+```

Diff for: packages/middleware/__tests__/integration/bootstrap/serverWithInit.ts

@@ -0,0 +1,20 @@
+import { apiClientFactory } from "../../../src/apiClientFactory";
+import * as api from "./api";
+
+const { createApiClient, init } = apiClientFactory({
+  onCreate: (config) => {
+    return {
+      config,
+      client: null,
+    };
+  },
+  api,
+  init: (config) => {
+    return {
+      ...config,
+      isInit: true,
+    };
+  },
+});
+
+export { createApiClient, init };

Diff for: packages/middleware/__tests__/integration/init.spec.ts

@@ -0,0 +1,27 @@
+import request from "supertest";
+import { createServer } from "../../src/index";
+
+describe("[Integration] Init", () => {
+  it("should extend the configuration", async () => {
+    const app = await createServer({
+      integrations: {
+        test_integration: {
+          location: "./__tests__/integration/bootstrap/serverWithInit",
+          configuration: {
+            foo: "bar",
+          },
+        },
+      },
+    });
+
+    const { body } = await request(app)
+      .post("/test_integration/getConfig")
+      .send([]);
+
+    expect(body).toEqual({
+      foo: "bar",
+      integrationName: "test_integration",
+      isInit: true,
+    });
+  });
+});

Diff for: packages/middleware/src/apiClientFactory/index.ts

@@ -178,7 +178,8 @@ const apiClientFactory = <
 
   createApiClient._predefinedExtensions = factoryParams.extensions || [];
 
-  return { createApiClient };
+  // TODO: Init function is being added to the return type but it's not being added nowhere here.
+  return { createApiClient, init: factoryParams.init };
 };
 
 export { apiClientFactory };

Diff for: packages/middleware/src/types/server.ts

@@ -113,6 +113,7 @@ export interface ApiClientFactoryParams<
     | Promise<{ client: CLIENT; config: ApiClientConfig }>
     | { client: CLIENT; config: ApiClientConfig };
   extensions?: ApiClientExtension<API>[];
+  init?: (configuration: CONFIG) => TObject;
 }
 
 export interface ApiClientFactory<
@@ -123,7 +124,7 @@ export interface ApiClientFactory<
   /**
    * Sets up integration config, runs once.
    */
-  init?: (configuration: TObject) => TObject;
+  init?: (configuration: CONFIG) => TObject;
 }
 
 export type CreateApiProxyFn = <CONFIG, API, CLIENT>(