Get started with Azure Cosmos DB for NoSQL using JavaScript

  • Article

APPLIES TO: NoSQL

This article shows you how to connect to Azure Cosmos DB for NoSQL using the JavaScript SDK. Once connected, you can perform operations on databases, containers, and items.

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Prerequisites

Set up your local project

  1. Create a new directory for your JavaScript project in a bash shell.

    mkdir cosmos-db-nosql-javascript-samples && cd ./cosmos-db-nosql-javascript-samples

  2. Create a new JavaScript application by using the npm init command with the console template.

    npm init -y

  3. Install the required dependency for the Azure Cosmos DB for NoSQL JavaScript SDK.

    npm install @azure/cosmos

Connect to Azure Cosmos DB for NoSQL

To connect to the API for NoSQL of Azure Cosmos DB, create an instance of the CosmosClient class. This class is the starting point to perform all operations against databases.

To connect to your API for NoSQL account using the Microsoft Entra, use a security principal. The exact type of principal depends on where you host your application code. The table below serves as a quick reference guide.

Where the application runs Security principal
Local machine (developing and testing) User identity or service principal
Azure Managed identity
Servers or clients outside of Azure Service principal

Import @azure/identity

The @azure/identity npm package contains core authentication functionality that is shared among all Azure SDK libraries.

  1. Import the @azure/identity npm package using the npm install command.

    npm install @azure/identity

  2. In your code editor, add the dependencies.

    const { DefaultAzureCredential } = require("@azure/identity");

Create CosmosClient with default credential implementation

If you're testing on a local machine, or your application will run on Azure services with direct support for managed identities, obtain an OAuth token by creating a DefaultAzureCredential instance. Then create a new instance of the CosmosClient class with the COSMOS_ENDPOINT environment variable and the TokenCredential object as parameters.

const { CosmosClient } = require("@azure/cosmos");
const { DefaultAzureCredential } = require("@azure/identity");

const credential = new DefaultAzureCredential();

const cosmosClient = new CosmosClient({ 
    endpoint, 
    aadCredentials: credential
});

Build your application

As you build your application, your code will primarily interact with four types of resources:

  • The API for NoSQL account, which is the unique top-level namespace for your Azure Cosmos DB data.

  • Databases, which organize the containers in your account.

  • Containers, which contain a set of individual items in your database.

  • Items, which represent a JSON document in your container.

The following diagram shows the relationship between these resources.

Diagram of the Azure Cosmos DB hierarchy including accounts, databases, containers, and items.

Each type of resource is represented by one or more associated classes. Here's a list of the most common classes:

Class Description
CosmosClient This class provides a client-side logical representation for the Azure Cosmos DB service. The client object is used to configure and execute requests against the service.
Database This class is a reference to a database that may, or may not, exist in the service yet. The database is validated server-side when you attempt to access it or perform an operation against it.
Container This class is a reference to a container that also may not exist in the service yet. The container is validated server-side when you attempt to work with it.

The following guides show you how to use each of these classes to build your application.

Guide Description
Create a database Create databases
Create a container Create containers
Create and read an item Point read a specific item
Query items Query multiple items

See also

Next steps

Create a database in Azure Cosmos DB for NoSQL using JavaScript