# Node.js and DAX
<a name="DAX.client.run-application-nodejs"></a>

Follow these steps to run the Node.js sample application on your Amazon EC2 instance.

**To run the Node.js sample for DAX**

1. Set up Node.js on your Amazon EC2 instance, as follows:

   1. Install node version manager (`nvm`).

      ```
      curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.35.3/install.sh | bash
      ```

   1. Use nvm to install Node.js.

      ```
      nvm install 12.16.3
      ```

   1. Test that Node.js is installed and running correctly.

      ```
      node -e "console.log('Running Node.js ' + process.version)"
      ```

      This should display the following message.

      `Running Node.js v12.16.3`

1. Install the DAX Node.js client using the node package manager (`npm`).

   ```
   npm install amazon-dax-client
   ```

1. Download the sample program source code (`.zip` file).

   ```
   wget http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/samples/TryDax.zip
   ```

   When the download is complete, extract the source files.

   ```
   unzip TryDax.zip
   ```

1. Run the following Node.js programs. The first program creates an Amazon DynamoDB table named `TryDaxTable`. The second program writes data to the table.

   ```
   node 01-create-table.js
   node 02-write-data.js
   ```

1. Run the following Node.js programs.

   ```
   node 03-getitem-test.js
   node 04-query-test.js
   node 05-scan-test.js
   ```

    Take note of the timing information—the number of milliseconds required for the `GetItem`, `Query`, and `Scan` tests.

1. In the previous step, you ran the programs against the DynamoDB endpoint. Run the programs again, but this time, the `GetItem`, `Query` and `Scan` operations are processed by your DAX cluster.

   To determine the endpoint for your DAX cluster, choose one of the following.
   + **Using the DynamoDB console**—Choose your DAX cluster. The cluster endpoint is shown on the console, as in the following example.

     ```
     dax://my-cluster.l6fzcv.dax-clusters.us-east-1.amazonaws.com
     ```
   + **Using the AWS CLI**—Enter the following command.

     ```
     aws dax describe-clusters --query "Clusters[*].ClusterDiscoveryEndpoint"
     ```

     The cluster endpoint is shown in the output, as in the following example.

     ```
     {
         "Address": "my-cluster.l6fzcv.dax-clusters.us-east-1.amazonaws.com",
         "Port": 8111,
         "URL": "dax://my-cluster.l6fzcv.dax-clusters.us-east-1.amazonaws.com"
     }
     ```

   Now run the programs again, but this time, specify the cluster endpoint as a command line parameter.

   ```
   node 03-getitem-test.js dax://my-cluster.l6fzcv.dax-clusters.us-east-1.amazonaws.com
   node 04-query-test.js dax://my-cluster.l6fzcv.dax-clusters.us-east-1.amazonaws.com
   node 05-scan-test.js dax://my-cluster.l6fzcv.dax-clusters.us-east-1.amazonaws.com
   ```

   Look at the rest of the output, and take note of the timing information. The elapsed times for `GetItem`, `Query`, and `Scan` should be significantly lower with DAX than with DynamoDB.

1. Run the following Node.js program to delete `TryDaxTable`.

   ```
   node 06-delete-table
   ```

For more information about these programs, see the following sections:
+ [01-create-table.js](DAX.client.run-application-nodejs.01-create-table.md)
+ [02-write-data.js](DAX.client.run-application-nodejs.02-write-data.md)
+ [03-getitem-test.js](DAX.client.run-application-nodejs.03-getitem-test.md)
+ [04-query-test.js](DAX.client.run-application-nodejs.04-query-test.md)
+ [05-scan-test.js](DAX.client.run-application-nodejs.05-scan-test.md)
+ [06-delete-table.js](DAX.client.run-application-nodejs.06-delete-table.md)