(0 , core_1.default) is not a function on lambda handler using @middy/core

Question

I'm trying to use middy on my lambda middlewares, my stack is created with TypeScript with Serverless v3, Node.js v18.

There is the minimal reproductive example:

tsconfig.json:

{
  "compilerOptions": {
    "preserveConstEnums": true,
    "strictNullChecks": true,
    "sourceMap": true,
    "allowJs": true,
    "target": "es5",
    "module": "CommonJS",
    "outDir": ".build",
    "moduleResolution": "node",
    "esModuleInterop": false,
    "lib": ["es2015"],
    "rootDir": "./"
  }
}

package.json:

{
  "main": "handler.js",
  "dependencies": {
    "@middy/core": "^4.7.0",
    "lodash": "^4.17.21"
  },
  "devDependencies": {
    "@types/lodash": "4.14.91",
    "@types/node": "^11.13.0",
    "serverless-offline": "^13.3.2",
    "serverless-plugin-typescript": "^1.1.7",
    "typescript": "^5.3.3"
  }
}

serverless.yml:

service: serverless-example

plugins:
  - serverless-plugin-typescript
  - serverless-offline

provider:
  name: aws
  runtime: nodejs18.x

functions:
  hello:
    handler: handler.handler
    events:
      - http:
          path: hello
          method: get

handler.ts

import middy from '@middy/core'

const myProtectedFunction= async (event, context) => {

  const userId = "123"
  return {
      statusCode: 200,
      body: JSON.stringify({ message: `Hello, user ${userId}!` }),
  };

};

export const handler = middy() .handler(myProtectedFunction);

After install serverless & dependencies just execute: serverless offline

and then make the request to the endpoint

Error image:

Answer 1

Here is what worked for me:

package.json

{
  "name": "s3-ts-1",
  "dependencies": {
    "@middy/core": "^4.7.0",
    "lodash": "^4.17.21"
  },
  "type": "module",
  "devDependencies": {
    "@types/lodash": "4.14.91",
    "@types/node": "^11.13.0",
    "serverless": "^3.38.0",
    "serverless-offline": "^13.3.2",
    "serverless-plugin-typescript": "^2.1.5",
    "typescript": "^5.3.3"
  }
}

Changes:

• specify type
• added serverless (this was because i have v2 in global scope, so added v3 in project scope)
• updated the packages in dev dependencies

tsconfig.json

{
  "compilerOptions": {
    "preserveConstEnums": true,
    "strictNullChecks": true,
    "sourceMap": true,
    "allowJs": false,
    "target": "es2021",
    "outDir": ".build",
    "moduleResolution": "node",
    "lib": ["es2015"],
    "baseUrl": "./",
    "esModuleInterop": true,
    "typeRoots": ["node_modules/@types"],
    "resolveJsonModule": true
  }
}

Changes: I made some changes from the middy doc here

serverless.yml and handler.ts: No changes

Run command: npx sls offline (Because i added local dependency for v3. You might not need npx).