tsynamo

Tsynamo

Type-safe DynamoDB query builder! Inspired by Kysely.

Usable with AWS SDK v3 DynamoDBDocumentClient.

[!NOTE] Currently this is a POC and a WIP. Currently, get-item and query operations are supported, but I am planning to add support for the rest of the operations too.

Installation

Available in NPM.

npm i tsynamo
pnpm install tsynamo
yarn add tsynamo

Usage

Creating a Tsynamo client

1. Define the types for your DynamoDB tables:

import { PartitionKey, SortKey } from "tsynamo";

export interface DDB {
  UserEvents: {
    userId: PartitionKey<string>;
    eventId: SortKey<number>;
    eventType: string;
    userAuthenticated: boolean;
  };
}

Notice that you can have multiple tables in the DDB schema. Nested attributes are supported too.

1. Create a DynamoDB document client:

import { DynamoDBClient } from "@aws-sdk/client-dynamodb";
import { DynamoDBDocumentClient } from "@aws-sdk/lib-dynamodb";

const ddbClient = DynamoDBDocumentClient.from(
  new DynamoDBClient({
    /* Configure client... */
  })
);

The document client must come from @aws-sdk/lib-dynamodb!

1. Create a Tsynamo client with the defined DynamoDB types and client:

const tsynamoClient = new Tsynamo<DDB>({
  ddbClient: dynamoDbDocumentClient,
});

Get item

await tsynamoClient
  .getItemFrom("UserEvents")
  .keys({
    userId: "123",
    eventId: 222,
  })
  .attributes(["userId"])
  .execute();

Query item

Partition key condition

await tsynamoClient
  .query("UserEvents")
  .keyCondition("userId", "=", "123")
  .execute();

Partition and sort key conditions

await tsynamoClient
  .query("UserEvents")
  .keyCondition("userId", "=", "123")
  .keyCondition("eventId", "<", 1000)
  .execute();

Simple filter expression

await tsynamoClient
  .query("UserEvents")
  .keyCondition("userId", "=", "123")
  .filterExpression("eventType", "=", "LOG_IN_EVENT")
  .execute();

Filter expression with a function

await tsynamoClient
  .query("UserEvents")
  .keyCondition("userId", "=", "123")
  .filterExpression("eventType", "begins_with", "LOG")
  .execute();

Multiple filter expressions

await tsynamoClient
  .query("UserEvents")
  .keyCondition("userId", "=", "123")
  .filterExpression("eventType", "begins_with", "LOG_IN")
  .orFilterExpression("eventType", "begins_with", "SIGN_IN")
  .execute();

Nested filter expressions

await tsynamoClient
  .query("UserEvents")
  .keyCondition("userId", "=", "123")
  .filterExpression("eventType", "=", "LOG_IN")
  .orFilterExpression((qb) =>
    qb
      .filterExpression("eventType", "=", "UNAUTHORIZED_ACCESS")
      .filterExpression("userAuthenticated", "=", true)
  )
  .orFilterExpression("eventType", "begins_with", "SIGN_IN")
  .execute();

This would compile as the following FilterExpression: eventType = "LOG_IN" OR (eventType = "UNAUTHORIZED_ACCESS" AND userAuthenticated = true)

NOT filter expression

await tsynamoClient
  .query("UserEvents")
  .keyCondition("userId", "=", "123")
  .filterExpression("NOT", (qb) =>
    qb.filterExpression("eventType", "=", "LOG_IN")
  )
  .execute();

This would compile as the following FilterExpression: NOT eventType = "LOG_IN", i.e. return all events whose types is not "LOG_IN"

Delete item

WIP

Put item

WIP

Update item

WIP

Scan

WIP

Contributors