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https://github.com/mits87/nestjs-dynamodb

Opinionated way to use DynamoDB with NestJS and typescript
https://github.com/mits87/nestjs-dynamodb

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Opinionated way to use DynamoDB with NestJS and typescript

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# NestJS DynamoDB Mapper

## Description

Opinionated way to use DynamoDB with NestJS and typescript, heavily inspired by [nestjs-typed-dynamodb](https://www.npmjs.com/package/nestjs-typed-dynamodb)

## Getting Started

First install this module

`npm install nestjs-dynamodb`

Notice that it will install as a dependency:

- [dynamodb-data-mapper-annotations](https://github.com/awslabs/dynamodb-data-mapper-js/tree/master/packages/dynamodb-data-mapper-annotations)
- [dynamodb-data-mapper](https://github.com/awslabs/dynamodb-data-mapper-js/tree/master/packages/dynamodb-data-mapper)

## Usage

In order to create a DynamoDB connection

**app.module.ts**

```typescript
import { Module } from '@nestjs/common';
import { DynamoDBModule } from 'nestjs-dynamodb';

import { CatsModule } from './cat.module.ts';

@Module({
imports: [
DynamoDBModule.forRoot({
AWSConfig: {},
dynamoDBOptions: {},
}),
CatsModule,
],
})
export class AppModule {}
```

**cats.module.ts**

```typescript
import { Module } from '@nestjs/common';
import { DynamoDBModule } from 'nestjs-dynamodb';

import { CatEntity } from './cat.entity';
import { CatsService } from './cats.service';

@Module({
imports: [DynamoDBModule.forFeature([CatEntity])],
providers: [CatsService],
})
export class CatsModule {}
```

To insert records to DynamoDB, you first need to create your table, for this we use [dynamodb-data-mapper-annotations](https://github.com/awslabs/dynamodb-data-mapper-js/tree/master/packages/dynamodb-data-mapper-annotations) (under the hood). Every decorator in that package is exposed in this package as well **BUT CAPITALIZED** .

**cat.entity.ts**

```typescript
import { Attribute, ReturnModel, Table } from 'nestjs-dynamodb';
import * as nanoid from 'nanoid';

@Table('cat')
class CatEntity {
@HashKey({ defaultProvider: nanoid })
pk: string;

@RangeKey()
sk: string;

@HashKey()
pk2: string;

@RangeKey()
sk2: string;

@Attribute()
age: number;

@Attribute()
alive?: boolean;

@Attribute()
createdAt: Date;

@Attribute({ defaultProvider: () => new Date() })
updatedAt: Date;

// This property will not be saved to DynamoDB.
notPersistedToDynamoDb: string;
}

export const Cat = ReturnModel();
```

Note: nanoid is only used a way to assign a random id, feel free to use whatever you want

**cats.service.ts**

```typescript
import { Injectable } from '@nestjs/common';
import { ReturnModel, InjectModel } from 'nestjs-dynamodb';

import { Cat } from './cat.entity';
import { CatInput } from './cat.input';

@Injectable()
export class CatsService {
constructor(@InjectModel(CatEntity) private readonly catModel: typeof Cat) {}

async all(input: Partial): Promise {
return this.catModel.query(input);
}

async find(id: string): Promise {
return this.catModel.find(id);
}

async create(input: CatInput): Promise {
return this.catModel.create(input);
}

async delete(input: string): Promise {
return this.catModel.delete(input);
}

async update(id: string, item: CatInput): Promise {
return this.catModel.update(id, item);
}
}
```

Now you can use your service as you wish!

## Async configuration

**app.module.ts**

```typescript
import { Module } from '@nestjs/common';
import { DynamoDBModule } from 'nestjs-dynamodb';

@Module({
imports: [
DynamoDBModule.forRootAsync({
imports: [ConfigModule],
useFactory: async (config: ConfigService) => ({
AWSConfig: {
region: 'local',
accessKeyId: 'null',
secretAccessKey: 'null',
},
dynamoDBOptions: {
endpoint: config.get('DYNAMODB_URL', 'localhost:8000'),
sslEnabled: false,
region: 'local-env',
},
}),
inject: [ConfigService],
}),
],
})
export class AppModule {}
```