Serverless Functions – AWS Lambda with TypeScript

Set up a Lambda project

npm init -y
npm i -D typescript @types/aws-lambda @aws-sdk/client-s3
npm i aws-lambda
npx tsc --init

Handler example

import { APIGatewayProxyEvent, APIGatewayProxyResult } from 'aws-lambda';

export const handler = async (event: APIGatewayProxyEvent): Promise<APIGatewayProxyResult> => {
  const name = event.queryStringParameters?.name ?? 'world';
  return {
    statusCode: 200,
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ message: `Hello, ${name}!` })
  };
};

Build & package

npm run build   # tsc → ./dist
zip -r function.zip dist/*

Upload function.zip via AWS Console or use the Serverless Framework:

npm i -g serverless
sls create -t aws-nodejs-typescript -p my-service

Testing locally with sam

sam local invoke "HelloFunction" -e event.json