Serverless computing is a popular approach to building and deploying applications that allows developers to focus on the code rather than infrastructure. One of the most common languages used for serverless applications is TypeScript, which offers type safety and other benefits over traditional JavaScript. In this tutorial, we will explore how to deploy TypeScript applications with serverless.


Prerequisites

To follow along with this tutorial, you should have:

  • Basic knowledge of TypeScript and Node.js
  • An AWS account with permissions to create Lambda functions and deploy API Gateway
  • The Serverless Framework installed globally on your machine (npm install -g serverless)


Step 1: Set up a new Serverless project

The first step is to create a new Serverless project using the Serverless Framework. Open your terminal and navigate to the directory where you want to create the project. Then, run the following command: 

serverless create --template aws-nodejs-typescript --path my-app

This will create a new Serverless project with TypeScript support in the my-app directory.


Step 2: Write your TypeScript code

Next, you will need to write your TypeScript code for your serverless function. By default, the create command above creates a simple "hello world" function in the handler.ts file.

Open the handler.ts file in your text editor and replace the hello function with your own code. For example, you could create a function that returns the current time:

export const getTime = async (): Promise<string> => {
  const now = new Date();
  return `The current time is ${now.toLocaleString()}`;
};

Note that we have exported this function so that it can be imported and used by other modules.


Step 3: Add serverless configuration

Now that you have written your TypeScript code, you will need to add some serverless configuration to tell Serverless how to deploy your code.

Open the serverless.yml file in your text editor and replace the contents with the following:

service: my-app
provider:
  name: aws
  runtime: nodejs14.x
  stage: dev
  region: us-east-1
functions:
  getTime:
    handler: handler.getTime
    events:
      - http:
          path: time
          method: get

This configuration file specifies that we are using AWS as our provider, and that we want to use the nodejs14.x runtime. It also defines a single function called getTime that maps to the handler.getTime function we defined earlier. Finally, it sets up an HTTP endpoint at /time that will trigger our function when it is called with an HTTP GET request.


Step 4: Deploy your code

Now that your code and configuration are in place, you can deploy your application to AWS using the Serverless Framework. Run the following command in your terminal:

serverless deploy

This command will create a new Lambda function and API Gateway endpoint in your AWS account, and will return a URL that you can use to access your function.


Step 5: Test your function

Finally, you can test your function by visiting the URL that was returned by the serverless deploy command. In our example, the URL would be https://1234567890.execute-api.us-east-1.amazonaws.com/dev/time.

If you visit this URL in your browser, you should see a response that includes the current time.


Conclusion

In this tutorial, we have explored how to deploy TypeScript applications with serverless. We started by setting up a new Serverless project with TypeScript support, and then wrote our own TypeScript code. We added serverless configuration to specify our AWS provider and our function, and then deployed our code to AWS using the Serverless Framework. Finally, we tested our function by visiting the API Gateway endpoint that was created during deployment.

This is just the beginning of what you can do with TypeScript and serverless. With TypeScript's type safety and other features, you can write more robust and maintainable serverless applications. And with the Serverless Framework, you can easily manage and deploy your applications to multiple cloud providers.

If you want to learn more about TypeScript and serverless, be sure to check out the official documentation for both TypeScript and the Serverless Framework. Happy coding!