Add docs on kysely adapter

Author: Papooch

docs/docs/06_plugins/01_available-plugins/01-transactional/04-kysely-adapter.md

@@ -0,0 +1,143 @@
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
+# Kysely adapter
+
+## Installation
+
+<Tabs>
+<TabItem value="npm" label="npm" default>
+
+```bash
+npm install @nestjs-cls/transactional-adapter-kysely
+```
+
+</TabItem>
+<TabItem value="yarn" label="yarn">
+
+```bash
+yarn add @nestjs-cls/transactional-adapter-kysely
+```
+
+</TabItem>
+<TabItem value="pnpm" label="pnpm">
+
+```bash
+pnpm add @nestjs-cls/transactional-adapter-kysely
+```
+
+</TabItem>
+</Tabs>
+
+## Registration
+
+```ts
+ClsModule.forRoot({
+    plugins: [
+        new ClsPluginTransactional({
+            imports: [
+              // module in which the Kysely is provided
+              KyselyModule
+            ],
+            adapter: new TransactionalAdapterKysely({
+                // the injection token of the Kysely client
+                kyselyInstanceToken: KYSELY,
+            }),
+        }),
+    ],
+}),
+```
+
+## Typing & usage
+
+The `tx` property on the `TransactionHost<TransactionalAdapterKysely>` is typed as `Kysely<any>` by default. To get the full typing, you need to supply your database type as the type parameter for the `TransactionalAdapterKysely` when injecting it:
+
+```ts
+constructor(
+    private readonly txHost: TransactionHost<
+        TransactionalAdapterKysely<Database>
+    >,
+) {}
+```
+
+:::tip
+
+This may get a bit too verbose, so you you might want to create a type alias for it:
+
+```ts
+type MyKyselyAdapter = TransactionalAdapterKysely<Database>;
+```
+
+and then inject it with
+
+```ts
+constructor(
+    private readonly txHost: TransactionHost<MyKyselyAdapter>,
+) {}
+```
+
+:::
+
+## Example
+
+```ts title="database.type.ts"
+interface Database {
+    user: User;
+}
+
+interface User {
+    id: Generated<number>;
+    name: string;
+    email: string;
+}
+```
+
+```ts title="user.service.ts"
+@Injectable()
+class UserService {
+    constructor(private readonly userRepository: UserRepository) {}
+
+    @Transactional()
+    async runTransaction() {
+        // highlight-start
+        // both methods are executed in the same transaction
+        const user = await this.userRepository.createUser('John');
+        const foundUser = await this.userRepository.getUserById(r1.id);
+        // highlight-end
+        assert(foundUser.id === user.id);
+    }
+}
+```
+
+```ts title="user.repository.ts"
+@Injectable()
+class UserRepository {
+    constructor(
+        private readonly txHost: TransactionHost<
+            TransactionalAdapterKysely<Database>
+        >,
+    ) {}
+
+    async getUserById(id: number) {
+        // highlight-start
+        // txHost.tx is typed as Kysely<Database>
+        return this.txHost.tx
+            .selectFrom('user')
+            .where('id', '=', id)
+            .selectAll()
+            .executeTakeFirst();
+        // highlight-end
+    }
+
+    async createUser(name: string) {
+        return this.txHost.tx
+            .insertInto('user')
+            .values({
+                name: name,
+                email: `${name}@email.com`,
+            })
+            .returningAll()
+            .executeTakeFirstOrThrow();
+    }
+}
+```

packages/transactional-adapters/transactional-adapter-kysely/test/transactional-adapter-kysely.spec.ts

@@ -40,15 +40,14 @@ class UserRepository {
     }
 
     async createUser(name: string) {
-        const created = await this.txHost.tx
+        return this.txHost.tx
             .insertInto('user')
             .values({
                 name: name,
                 email: `${name}@email.com`,
             })
             .returningAll()
             .executeTakeFirstOrThrow();
-        return created;
     }
 }