Deploy transpiled TypeScript code in Lambda with .zip file archives

Initialize the application using the Hello World TypeScript template.

sam init --app-template hello-world-typescript --name sam-app --package-type Zip --runtime nodejs18.x

(Optional) The sample application includes configurations for commonly used tools, such as ESLlint for code linting and Jest for unit testing. To run lint and test commands:

cd sam-app/hello-world
npm install
npm run lint
npm run test

Build the app.

cd sam-app
sam build

Deploy the app.

sam deploy --guided

Follow the on-screen prompts. To accept the default options provided in the interactive experience, respond with Enter.

The output shows the endpoint for the REST API. Open the endpoint in a browser to test the function. You should see this response:

{"message":"hello world"}

This is a public API endpoint that is accessible over the internet. We recommend that you delete the endpoint after testing.

sam delete

Create a project directory for your new application.

mkdir hello-world
cd hello-world

Initialize the app.

cdk init app --language typescript

Add the @types/aws-lambda package as a development dependency. This package contains the type definitions for Lambda.

npm install -D @types/aws-lambda

Open the lib directory. You should see a file called hello-world-stack.ts. Create two new files in this directory: hello-world.function.ts and hello-world.ts.

Open hello-world.function.ts and add the following code to the file. This is the code for the Lambda function.

import { Context, APIGatewayProxyResult, APIGatewayEvent } from 'aws-lambda';

export const handler = async (event: APIGatewayEvent, context: Context): Promise<APIGatewayProxyResult> => {
    console.log(`Event: ${JSON.stringify(event, null, 2)}`);
    console.log(`Context: ${JSON.stringify(context, null, 2)}`);
    return {
        statusCode: 200,
        body: JSON.stringify({
            message: 'hello world',
        }),
    };
};

Open hello-world.ts and add the following code to the file. This contains the NodejsFunction construct, which creates the Lambda function, and the LambdaRestApi construct, which creates the REST API.

import { Construct } from 'constructs';
import { NodejsFunction } from 'aws-cdk-lib/aws-lambda-nodejs';
import { LambdaRestApi } from 'aws-cdk-lib/aws-apigateway';
  
export class HelloWorld extends Construct {
  constructor(scope: Construct, id: string) {
    super(scope, id);
    const helloFunction = new NodejsFunction(this, 'function');
    new LambdaRestApi(this, 'apigw', {
      handler: helloFunction,
    });
  }
}

The NodejsFunction construct assumes the following by default:

You can change this behavior and configure other esbuild parameters. For more information, see Configuring esbuild in the AWS CDK API reference.

Open hello-world-stack.ts. This is the code that defines your AWS CDK stack. Replace the code with the following:

import { Stack, StackProps } from 'aws-cdk-lib';
import { Construct } from 'constructs';
import { HelloWorld } from './hello-world';
  
export class HelloWorldStack extends Stack {
  constructor(scope: Construct, id: string, props?: StackProps) {
    super(scope, id, props);
    new HelloWorld(this, 'hello-world');
  }
}

from the hello-world directory containing your cdk.json file, deploy your application.

cdk deploy

The AWS CDK builds and packages the Lambda function using esbuild, and then deploys the function to the Lambda runtime. The output shows the endpoint for the REST API. Open the endpoint in a browser to test the function. You should see this response:

{"message":"hello world"}

This is a public API endpoint that is accessible over the internet. We recommend that you delete the endpoint after testing.

On your local machine, create a project directory for your new function.

Create a new Node.js project with npm or a package manager of your choice.

npm init

Add the @types/aws-lambda and esbuild packages as development dependencies. The @types/aws-lambda package contains the type definitions for Lambda.

npm install -D @types/aws-lambda esbuild

Create a new file called index.ts. Add the following code to the new file. This is the code for the Lambda function. The function returns a hello world message. The function doesn’t create any API Gateway resources.

import { Context, APIGatewayProxyResult, APIGatewayEvent } from 'aws-lambda';

export const handler = async (event: APIGatewayEvent, context: Context): Promise<APIGatewayProxyResult> => {
  console.log(`Event: ${JSON.stringify(event, null, 2)}`);
  console.log(`Context: ${JSON.stringify(context, null, 2)}`);
  return {
      statusCode: 200,
      body: JSON.stringify({
          message: 'hello world',
      }),
   };
};

Add a build script to the package.json file. This configures esbuild to automatically create the .zip deployment package. For more information, see Build scripts in the esbuild documentation.

Build the package.

npm run build

Create a Lambda function using the .zip deployment package. Replace the highlighted text with the Amazon Resource Name (ARN) of your execution role.

aws lambda create-function --function-name hello-world --runtime "nodejs18.x" --role arn:aws:iam::123456789012:role/lambda-ex --zip-file "fileb://dist/index.zip" --handler index.handler

Run a test event to confirm that the function returns the following response. If you want to invoke this function using API Gateway, create and configure a REST API.

{
  "statusCode": 200,
  "body": "{\"message\":\"hello world\"}"
}