Base Service

You can inject BaseService into Services or Resolvers. BaseService can be thought of as a wrapper of mongoose Model. It provides basic CRUD operations with context and Hooks.

Interface

Below is the type of BaseService, which shows the methods and their parameters.

class BaseService<T = any, Context = any> {
    model: PaginateModel<T>;
    create(ctx: Context, input: Partial<T>): Promise<T>;
    update(ctx: Context, input: Partial<T> & { id: ObjectId }): Promise<T>;
    findById(ctx: Context, filter: { _id: ObjectId }): Promise<T>;
    findByIdNullable(ctx: Context, filter: { _id: ObjectId }): Promise<T | null>;
    findOne(ctx: Context, filter: FilterQuery<T>): Promise<T>;
    findOneNullable(ctx: Context, filter: FilterQuery<T>): Promise<T | null>;
    findOne(ctx: Context, filter: mongoose.FilterQuery<T>): Promise<T>;
    findAll(ctx: Context, filter: mongoose.FilterQuery<T>, sort: object): Promise<T[]>;
    remove(ctx: Context, id: ObjectId, options?: RemoveOptions): Promise<SuccessResponse>;
    paginate(ctx: Context, filter: FilterQuery<T>, sort: object, page: number, limit: number): PaginateResult;
}
💡

update and remove methods use findOne under the hood.

Inject BaseService

Below is an example of how to inject BaseService

import { BaseService, InjectBaseService } from 'dryerjs';
 
type Context = { user: { id: ObjectId, role: 'admin' | 'user' } }
 
@Injectable()
class AuthService {
  constructor(@InjectBaseService(User) public userService: BaseService<User, Context>) {}
 
  async refreshToken(ctx: Context) {
    const user = await this.userService.findOne(ctx, { _id: ctx.user.id });
    // fake function to generate token
    return getTokenFromUser(user);
  }
}

Use Mongoose Model

BaseService only covers the basic CRUD operations with context, if you want to use more advanced features or context free, you can use mongoose Model directly by accessing model property of BaseService.

@Injectable()
class AuthService {
  constructor(@InjectBaseService(User) public userService: BaseService<User, Context>) {}
 
  async isEmailTaken(email: string) {
    return await this.userService.model.exists({ email });
  }
}

Context object

Context normally comes from the Resolvers, but you can also create your own context object to pass into BaseService methods.

@Injectable()
class AuthService {
  async cron() {
    const adminContext: Context = { user: { id: '000000000000000000000000', role: 'admin' } };
    const oneYearAgo = new Date(Date.now() - 365 * 86400 * 1000);
    const users = await this.userService.findAll(ctx, { lastLoggedInAt: { $lt: oneYearAgo } });
    for (const user of users) {
      await this.userService.update(adminContext, { id: user.id, status: 'inactive' });
    }
  }
}

Compare with using mongoose Model directly, calling update method with BaseService will trigger beforeUpdateHook and afterUpdateHook. Which could be extremely important if you have some logic in the hooks.

HookType Functions