nestjs-kysely

nestjs-kysely implements a module that provides the client of Kysely, which is a type-safe query builder.

install

yarn add nestjs-kysely kysely

Example

yarn add nestjs-kysely kysely mysql2

Register KyselyModule for your app.

import { Module } from "@nestjs/common";
import { MysqlDialect } from "kysely";
import { createPool } from "mysql2";
import { KyselyModule } from "nestjs-kysely";
import { AppController } from "./app.controller";

@Module({
  imports: [
    KyselyModule.forRoot({
      dialect: new MysqlDialect({
        pool: createPool({
          host: "127.0.0.1",
          user: "root",
          password: "password",
          database: "kysely_test",
        }),
      }),
    }),
  ],
  controllers: [AppController],
})
export class AppModule {}

You can then inject the Kysely client into any of your injectables by using a custom decorator.

import { Controller, Get } from "@nestjs/common";
import { InjectKysely } from "nestjs-kysely";
import { DB } from "./@types";

@Controller()
export class AppController {
  constructor(@InjectKysely() private readonly db: DB) {}

  @Get()
  async getHello(): Promise<string> {
    const result = await this.db
      .selectFrom("person")
      .innerJoin("pet", "pet.owner_id", "person.id")
      .selectAll()
      .execute();

    return JSON.stringify(result);
  }
}

Multiple namespace

Register KyselyModule with multiple DBs for your app.

Example forRoot

import { Module } from "@nestjs/common";
import { MysqlDialect, SqliteDialect } from "kysely";
import { createPool } from "mysql2";
import Database from "better-sqlite3";
import { KyselyModule } from "nestjs-kysely";
import { AppController } from "./app.controller";

@Module({
  imports: [
    KyselyModule.forRoot([
      {
        namespace: 'mysql',
        dialect: new MysqlDialect({
          pool: createPool({
            host: "127.0.0.1",
            user: "root",
            password: "password",
            database: "kysely_test",
          }),
        }),
      },
      {
        namespace: 'sqlite',
        dialect: new SqliteDialect({
          database: new Database(),
        }),
      }

    ]),
  ],
  controllers: [AppController],
})
export class AppModule {}

Example forRootAsync

import { Module } from "@nestjs/common";
import { MysqlDialect, SqliteDialect } from "kysely";
import { createPool } from "mysql2";
import Database from "better-sqlite3";
import { KyselyModule } from "nestjs-kysely";
import { AppController } from "./app.controller";

@Module({
  imports: [
    KyselyModule.forRootAsync({
      namespace: 'mysql',
      useFactory: () => (
        {
          dialect: new MysqlDialect({
            pool: createPool({
              host: "127.0.0.1",
              user: "root",
              password: "password",
              database: "kysely_test",
            }),
          }),
        }
      )
    }),
    KyselyModule.forRootAsync({
      namespace: 'sqlite',
      useFactory: () => (
        {
          dialect: new SqliteDialect({
            database: new Database(),
          }),
        }
      )
    }),
  ],
  controllers: [AppController],
})
export class AppModule {}

Use it

You can then inject the Kysely client into any of your injectables by using a custom decorator with namespace as input.

import { Controller, Get } from "@nestjs/common";
import { InjectKysely } from "nestjs-kysely";
import { DB } from "./@types";

@Controller()
export class AppController {
  constructor(
    @InjectKysely('mysql') private readonly mysql: Kysely<unknown>,
    @InjectKysely('sqlite') private readonly sqlite: Kysely<unknown>,
  ) {}

  @Get()
  async getHello(): Promise<string> {
    const result = await this.db
      .selectFrom("person")
      .innerJoin("pet", "pet.owner_id", "person.id")
      .selectAll()
      .execute();

    return JSON.stringify(result);
  }
}

License

MIT