Type checking and autocompletion in Lambda without TypeScript!

Did you know that you don't need to use TypeScript to get type checking and autocomplete when writing your Lambdas in Node.js? In this short, we show you how you can simply rely on JSDoc annotations to get in-editor support for type-based auto-completion and type-checking! We will be demonstrating that with a Lambda implementing the API Gateway LambdaProxy integration (the most widely used for APIs). You just need to install the `lambda` types with:

```
npm i --save-dev @types/aws-lambda
```

Then you can simply import your types using the following JSDoc notation:

```
@param {import('aws-lambda').APIGatewayEvent} event
@param {import('aws-lambda').Context} context
```

Full code available here: https://gist.github.com/lmammino/ad16b389742cf78e804ecd988c192e35

TypeScript is great, but JSDoc can give you most of the same advantages without having to rely on transpilation.

Did you enjoy this short? Did you know about this trick? Let us know in the comments!

Credits:

Music by prazkhanal from Pixabay