dynamodb-ts-model

A DynamoDB model implementation with full TypeScript type support.

This module allows you to create fully type-safe DynamoDB models describing your data, including keys, indices etc. It also supports

• Clean type-safe interface for all table operations, transactions and batch operations
• Auto-generated properties when adding or updating items, useful for timestamps, random IDs etc
• Triggers: register callback functions for modifications to a model

Installation

$ npm install dynamodb-ts-model

Usage

Build a model with key, indices, auto-created attributes and triggers.

import DynamoClient from 'dynamodb-ts-model';

type Person = {
  id: string;
  name: string;
  email?: string;
  age?: number;
};

const client = new DynamoClient();

const now = () => new Date().toJSON();
 

const persons = client.model<Person>('persons')
  .withKey('id')
  .withIndex('name-age-index', 'name', 'age')
  .withCreator(x => ({id: uuid.v4(), createdTime: now(), modifiedTime: now()}))
  .withUpdater(x => ({modifiedTime: now()}))
  .withTrigger((item, command, model) => console.log(`Trigger: ${model.name}.${command}: ${JSON.stringify(item)}))
  .build();

Querying for items

Conditions and update expressions use the dynamodb-expressions module.

const {items} = await persons.query({
  indexName: 'name-age-index', 
  keyConditions: {name: 'Henrik', age: Condition.ge(18)}
});

There is also built-in AsyncIterator support to enable simple iteration of scanned or queried items without bothering with nextPageToken, using for await ... of syntax.

Iterate through all persons:

for await (const item of persons.scanIterator()) {
  console.log(item.name, item.age);
}

Iterate through all persons named Alice over the age of 25:

for await (const item of persons.queryIterator({
  indexName: 'name-age-index',
  keyConditions: {
    name: 'Alice',
    age: Condition.ge(25)
  }
})) {
  console.log(item.name, item.age);
}

Transactions

await client.transaction()
  .put(persons, {item: {name: 'John Doe'}}, {item: {name: 'Jane Doe'}})
  .delete(persons, {key: {id: 'foo'}})
  .commit()