Nestjs-dynamoose NPM

Description

Installation

$ npm install --save nestjs-dynamoose dynamoose

Example Project

A AWS NestJS Starter project has been created to demo the usage of this library.

Quick Start

1. Add import into your app module

src/app.module.ts

import { DynamooseModule } from 'nestjs-dynamoose';
import { UserModule } from './user/user.module';

@Module({
 imports: [
   DynamooseModule.forRoot(),
   UserModule,
 ],
})
export class AppModule {

forRoot() optionally accepts the following options defined by DynamooseModuleOptions:

interface DynamooseModuleOptions {
  aws?: {
    accessKeyId?: string;
    secretAccessKey?: string;
    region?: string;
  };
  local?: boolean | string;
  ddb?: DynamoDB;
  table?: TableOptionsOptional;
  logger?: boolean | LoggerService;
}

There is also forRootAsync(options: DynamooseModuleAsyncOptions) if you want to use a factory with dependency injection.

2. Create a schema

src/user/user.schema.ts

import { Schema } from 'dynamoose';

export const UserSchema = new Schema({
  id: {
    type: String,
    hashKey: true,
  },
  name: {
    type: String,
  },
  email: {
    type: String,
  },
});

src/user/user.interface.ts

export interface UserKey {
  id: string;
}

export interface User extends UserKey {
  name: string;
  email?: string;
}

UserKey holds the hashKey/partition key and (optionally) the rangeKey/sort key. User holds all attributes of the document/item. When creating this two interfaces and using when injecting your model you will have typechecking when using operations like Model.update().

3. Add the models you want to inject to your modules

This can be a feature module (as shown below) or within the root AppModule next to DynamooseModule.forRoot().

src/user/user.module.ts

import { DynamooseModule } from 'nestjs-dynamoose';
import { UserSchema } from './user.schema';
import { UserService } from './user.service';

@Module({
  imports: [
    DynamooseModule.forFeature([{
      name: 'User',
      schema: UserSchema,
      options: {
        tableName: 'user',
      },
    }]),
  ],
  providers: [
    UserService,
    ...
  ],
})
export class UserModule {}

options.tableName is optional. If it is not provided, name will be used as the table name.

There is also forFeatureAsync(factories?: AsyncModelFactory[]) if you want to use a factory with dependency injection. Notes that the first parameter of the useFactory callback is reserved for future use, so please just add _, to ignore it.

The following example will use USER_TABLE_NAME environment variable as the table name.

import { DynamooseModule } from 'nestjs-dynamoose';
import { UserSchema } from './user.schema';
import { UserService } from './user.service';

@Module({
  imports: [
    ConfigModule.forRoot({ isGlobal: true }),
    DynamooseModule.forFeatureAsync([
      {
        name: 'User',
        useFactory: (_, configService: ConfigService) => {
          return {
            schema: UserSchema,
            options: {
              tableName: configService.get<string>('USER_TABLE_NAME'),
            },
          };
        },
        inject: [ConfigService],
      },
    ]),
  ],
  providers: [
    UserService,
    ...
  ],
})
export class UserModule {}

4. Inject and use your model

src/user/user.service.ts

import { Injectable } from '@nestjs/common';
import { InjectModel, Model } from 'nestjs-dynamoose';
import { User, UserKey } from './user.interface';

@Injectable()
export class UserService {
  constructor(
    @InjectModel('User')
    private userModel: Model<User, UserKey>,
  ) {}

  create(user: User) {
    return this.userModel.create(user);
  }

  update(key: UserKey, user: Partial<User>) {
    return this.userModel.update(key, user);
  }

  findOne(key: UserKey) {
    return this.userModel.get(key);
  }

  findAll() {
    return this.userModel.scan().exec();
  }
}

Additional Example

1. Transaction Support

Both User and Account model objects will commit in same transaction.

import { Injectable } from '@nestjs/common';
import { InjectModel, Model, TransactionSupport } from 'nestjs-dynamoose';
import { User, UserKey } from './user.interface';
import { Account, AccountKey } from './account.interface';

@Injectable()
export class UserService extends TransactionSupport {
  constructor(
    @InjectModel('User')
    private userModel: Model<User, UserKey>,
    @InjectModel('Account')
    private accountModel: Model<Account, AccountKey>,
  ) {
    super();
  }

  async create(user: User, account: Account) {
    await this.transaction([
      this.userModel.transaction.create(user),
      this.accountModel.transaction.create(account),
    ]);
  }
}

2. Serializers Support

Define the additional serializers under DynamooseModule.forFeature().

@Module({
  imports: [
    DynamooseModule.forFeature([
      {
        name: 'User',
        schema: UserSchema,
        serializers: {
          frontend: { exclude: ['status'] },
        },
      },
    ]),
  ],
  ...
})
export class UserModule {}

Call the serialize function to exclude the status field.

@Injectable()
export class UserService {
  ...
  async create(user: User) {
    const createdUser = await this.userModel.create(user);
    return createdUser.serialize('frontend');
  }
  ...
}