AWS SDK for JavaScript v3 提供了用于与 Amazon DynamoDB 和 Amazon DynamoDB Accelerator (DAX) 交互的 API。要使用 DAX，需要安装 aws-sdk 包和 amazon-dax-client 包。以下是使用 DAX 的 JavaScript 代码示例：

const AWS = require('aws-sdk');
const AmazonDaxClient = require('amazon-dax-client');

const dax = new AmazonDaxClient({
  endpoints: ['mydaxcluster.xxxxxx.clustercfg.dax.use1.cache.amazonaws.com:8111'],
  region: 'us-east-1',
  accessKeyId: 'XXXXX',
  secretAccessKey: 'XXXXX'
});

const dynamodb = new AWS.DynamoDB({ region: 'us-east-1', endpoint: 'http://localhost:8000', maxRetries: 0, httpOptions: { agent: dax } });

const params = {
  TableName: 'my-table',
  Key: { 
    'my-key': { S: 'value' }
  }
};

dynamodb.getItem(params, function(err, data) {
  if (err) console.log(err, err.stack);
  else console.log(data);
});