[Typescript] Runtime type error

[kazkansouh]

Describe the bug

Using Serverless framework with serverless-plugin-typescript. At runtime, the following type error is produced:

(0 , core_1.default) is not a function

To Reproduce
How to reproduce the behaviour:

See https://github.com/kazkansouh/middy-bug for a self contained example.

1. Create serverless framework project with serverless-plugin-typescript.
2. Code for handler

   import middy from '@middy/core'
   import { APIGatewayProxyHandler } from 'aws-lambda'
   const gatewayHandler: APIGatewayProxyHandler = async (event, context) => {
     const response = { result: 'success', message: 'payment processed correctly' }
     return { statusCode: 200, body: JSON.stringify(response) }
   }
   export const handler = middy(gatewayHandler)

3. Deploy code, and then access endpoint.
4. Thrown error (from AWS cloudwatch logs)

   2022-02-20 13:37:45.787 ERROR   Uncaught Exception      {"errorType":"TypeError","errorMessage":"(0 , core_1.default) is not a function","stack":["TypeError: (0 , core_1.default) is not a function","    at Object.<anonymous> (/var/task/src/fulfillment.js:193:38)","    at Module._compile (internal/modules/cjs/loader.js:1085:14)","    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1114:10)","    at Module.load (internal/modules/cjs/loader.js:950:32)","    at Function.Module._load (internal/modules/cjs/loader.js:790:12)","    at Module.require (internal/modules/cjs/loader.js:974:19)","    at require (internal/modules/cjs/helpers.js:93:18)","    at _tryRequireFile (/var/runtime/UserFunction.js:63:32)","    at _tryRequire (/var/runtime/UserFunction.js:151:20)","    at _loadUserApp (/var/runtime/UserFunction.js:197:12)"]}
   

Expected behaviour

Does not raise type error.

Environment (please complete the following information):

$ npm ls
[email protected] /dev/shm/bug/middy-bug
├── @middy/[email protected]
├── @types/[email protected]
├── [email protected]
├── [email protected]
└── [email protected]

[willfarrell]

This might be resolved by middy hopefully to moving to esm for v3. But, there are still some unknowns from AWS on what they are doing. aws-powertools/powertools-lambda-typescript#465 might have a workaround for you.

#584

[kazkansouh]

@willfarrell Thankyou for the help. Yep, you are correct. adding esModuleInterop to tsconfig.json works.