Lambda Proxy autocomplete and type checking with JSDoc (and no TypeScript!)

README.md

How to get type checking and autocompletion in your IDE without TypeScript for your AWS Lambda code

A quick demo that shows how JSDoc annotations can help you to get autocompletion and type checking without having to write (and transpile!) TypeScript code.

The video version is available here: https://youtube.com/shorts/60zUEc_vs1o

For more AWS tutorials, follow us at @AWSBites

handler.js

// @ts-check

// Let's add type support to this lambda proxy lambda
// without TypeScript!!!

// let's make it strict!

/**
 * 
 * @param {import('aws-lambda').APIGatewayEvent} event 
 * @param {import('aws-lambda').Context} context 
 * @returns {Promise<import('aws-lambda').APIGatewayProxyResult>}
 */
export default async function handler(event, context) {
  const username = event?.queryStringParameters?.name || 'world'
  const functionName = context.functionName
  const bla = event.bla
  return {
    body: JSON.stringify({ message: `Hello ${username} by ${functionName}!` })
  }
}

package.json

{
  "name": "example",
  "version": "1.0.0",
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@types/aws-lambda": "^8.10.107"
  },
  "type": "module"
}