@bippo-libs/aws-dynamodb-client

aws-dynamodb-client

Use decorators on model classes to simplify the inputs to the DynamoDB client and receive model classes as an output. Internally uses @aws-sdk/lib-dynamodb v3 and class-validator

Installation

npm install @bippo-libs/aws-dynamodb-client

Usage

Create a model class and use decorators for attributes and keys. Properties without decorators are ignored when the model is mapped to a dynamodb item. Here, a DTO (Data Transfer Object) class is also defined so that keys and meta data like createdOn remain in the data access layer. Note that attributes can have aliases, and that some attributes are properties, others defined using methods, and still others with accessors. Attributes defined using properties and methods are overwritten with the values pulled from dynamodb whereas accessors (in this case getters) are not. This means after an item/model has been retrieved from dynamodb, updatedOn will always assume the datetime value of when it is written to dynamodb whereas createdOn will retain the value from dynamodb by default.

import {
  Attribute,
  IndexPartitionKey,
  IndexSortKey,
  Model,
  PartitionKey,
  SortKey,
  Table,
} from '@bippo-libs/aws-dynamodb-client';

@Table('MyTable')
export class PersonDTO extends Model<PersonDTO> {
  @Attribute()
  public phone: string;

  @Attribute()
  public email: string;

  @Attribute('dob')
  public dateOfBirth: Date;

  @Attribute()
  public firstName: string;

  @Attribute()
  public lastName: string;

  public club: string;
}

@Table('MyTable')
export class PersonModel extends PersonDTO {
  @PartitionKey()
  public PK() {
    return `CLUB#${this.club}`;
  }

  @SortKey()
  public SK() {
    return `PERSON#${this.firstName}#${this.lastName}`;
  }

  @IndexPartitionKey('GSI1')
  public get GSI1PK(): string {
    return `LASTNAME#${this.lastname}`;
  }

  @IndexSortKey('GSI1')
  public get GSI1SK(): string {
    return this.email;
  }

  @Attribute()
  public createdOn() {
    return new Date().toISOString();
  }

  @Attribute()
  public get updatedOn() {
    return new Date().toISOString();
  }
}