AWS with Node.js preview

The AWS SDK for JavaScript v3 modular packages (@aws-sdk/client-s3, etc.) integrate with Node.js servers and Lambda handlers using async/await.

Install modular client

npm install @aws-sdk/client-s3
export AWS_PROFILE=sandbox
export AWS_REGION=us-east-1

List buckets

import { S3Client, ListBucketsCommand } from '@aws-sdk/client-s3';

const client = new S3Client({ region: 'us-east-1' });
const out = await client.send(new ListBucketsCommand({}));
console.log(out.Buckets?.map(b => b.Name));

Practice: Run SDK examples locally with sandbox credentials via AWS_PROFILE=sandbox. Never commit real keys—use IAM roles in deployed environments.

Lambda handler pattern

export const handler = async (event) => {
  // IAM execution role grants permissions
  return { statusCode: 200, body: JSON.stringify({ ok: true }) };
};

Best practices

• Import only clients you need—smaller Lambda bundles
• Reuse client outside handler in Lambda for connection reuse
• Use AWS SDK middleware for logging and retries consciously

Important interview questions and answers

1. Q: SDK v3 vs v2?
   A: v3 is modular with command pattern; smaller tree-shaken bundles for Lambda.
2. Q: Why reuse S3Client in Lambda?
   A: Avoids creating new clients per invocation—faster warm starts.

Self-check

1. What npm package lists S3 buckets in SDK v3?
2. Why avoid access keys in Node.js source code?

Tip: Import only @aws-sdk/client-* packages you need to shrink Lambda bundles.