Cosmonaut

Cosmonaut is an unofficial (Object Data Mapper) ODM for Cosmos DB. I grew tired of copying a utility library to use between projects. It has a strong emphasis on modularity and type-safety, while also aiming to be pleasant to use for non-TypeScript consumers.

npm i --save cosmonaut-odm

Unlike other TypeScript ORMs/ODMs, we don't use decorators. Decorators can be burdensome or impossible to deal with, especially for vanilla JS consumers and lack type-safety. Instead, the basis of everything is the well-typed "schema" from which the world is derived.

Features

• Schema builder and typesafe schemas
• Basic object data model
• Atomic operations
• Validation
• Transformation functions
• Query support
• RU telemetry
• Pagination helpers
• TTL normalization
• 'relationships'

Complete API docs here.

Quickstart

import { Model, createSchema, asType } from 'cosmonaut-odm';

// Define a new container in Cosmos DB
const schema = createSchema('users')
  .partitionKey('/id')
  // You give types to the schema via the `asType` helper function
  .field('username', asType<string>())
  // You can pass in a JSON schema used to validate the type in the third argument
  .field('favoriteColors', asType<string[]>(), {
    type: 'array',
    items: { type: 'string', }
    uniqueItems: true,
  });

// Use the `Model` function to create the class encapsulating a schema. You can
// then use and extend this like normal JavaScript classes.
class User extends Model(schema) {}

// Provide the database connection to models. You can also pass this in
// individually to method calls, if you'd like
connectModels(new CosmosClient({ /* ... */ }).database('my-db'));

// Make sure the container exists...
await User.container().createIfNotExists();

// And create a user!
const user = new User({
  id: '42',
  username: 'Connor',
  favoriteColors: ['blue'],
});

// Properties are accessible in the `props` object.
user.props.favoriteColors.push('green');

// Save, delete, and so on.
await user.save();

Contributing

Here's how to run tests:

1. Clone the repo, and run npm install
2. In one terminal, run npm run watch:tsc
3. In another, you can npm run test:unit or npm run watch:test to rerun them

By default, it'll run against Vercel's cosmosdb-server implementation. However, you can run it against a local Cosmos DB emulator by running npm run test:unit:emulator. This is slower and requires Windows or Windows containers, but is useful to sanity check changes.