Just change the .mjs extension of index.mjs to index.js

This is seen if you are using NodeJS 14 or above which no longer has `require` by default. See https://nodejs.org/api/esm.html#no-require-exports-or-moduleexports You can fix this by adding these two lines at the top of your file. ``` import { createRequire } from 'module'; const require = createRequire(import.meta.url); ```

Hi, try replacing the line: ``` module.exports.handler = async (event) => { ``` with ``` export const handler = async (event) => { ``` You can import you modules outside of the handler with the command below and then use within the handler: ``` import {StringMessage} from './StringMessage.mjs'; ```

Use:

import { DynamoDB } from '@aws-sdk/dynamodb';

But also rename your index.js file to index.mjs, that should do the trick.

Hey @khaper bas22 (https://teamtreehouse.com/khaperbas22) , thanks for sharing your question! I understand you're encountering issues with require in your Node.js project related to ES modules. This can happen due to several reasons, and I'd be happy to help troubleshoot. If you are using Treehouse Workspaces, it is usually configured to work with the course. However, if you are working locally, there might be some environmental differences between your machine and the teacher's. Here are some common issues and solutions: Node.js Version: Ensure you are using a Node.js version that supports ES modules without the need for the --experimental-modules flag. Versions from 14.0.0 onward fully support ES modules. package.json Configuration: Set the "type" field in your package.json to "module" to indicate the use of ES modules: json { "type": "module" } Unfortunately, that's all I can offer at the moment as I'm unsure of what you're seeing and how Node.js has been set up on your machine. If you can provide more specific details, code snippets, or error messages, I can give more targeted assistance!

To upgrade to Node.js 18, you have to change the code to make the function work again. I don't use zip files, config files or layers.

Steps to upgrade your AWS Lambda function:

1. Change the filename of index.js to index.mjs

File names ending in .mjs are always treated as ES modules. File names ending in .js inherit their type from the package.

Reference: https://aws.amazon.com/blogs/compute/using-node-js-es-modules-and-top-level-await-in-aws-lambda/

You should rename your index.js file to index.mjs to prevent one of the following errors:

• SyntaxError: Cannot use import statement outside a module

• SyntaxError: Unexpected token 'export'

2. Change your handler from CommonJS module handler to ES module handler

You must update the way you define your handler to prevent one of the following errors:

• Runtime.HandlerNotFound: index.handler is undefined or not exported

• ReferenceError: exports is not defined in ES module scope

Reference: https://docs.aws.amazon.com/lambda/latest/dg/nodejs-handler.html

// Before NodeJS 18
exports.handler = async function (event, context) {
  console.log("EVENT: \n" + JSON.stringify(event, null, 2));
  return context.logStreamName;
}; 

// NodeJS 18 and above
export const handler = async (event, context) => {
  console.log("EVENT: \n" + JSON.stringify(event, null, 2));
  return context.logStreamName;
};

3. Change the way you import your modules

You cannot use the "require" keyword anymore. You will get the following error when you do:

• ReferenceError: require is not defined in ES module scope, you can use import instead

It is important to know that since NodeJS 18 you cannot import the complete AWS SDK anymore, but you have to specify which modules you need, or you will get the following error:

• Runtime.ImportModuleError: Error: Cannot find module 'aws-sdk'

Reference: https://aws.amazon.com/blogs/compute/node-js-18-x-runtime-now-available-in-aws-lambda/

// Before NodeJS 18
const AWS = require("aws-sdk");
const https = require("https");
const querystring = require("querystring"); 

// NodeJS 18 and above. In this example the module "client-sns" is imported from the AWS SDK.
import * as AWS from "@aws-sdk/client-sns";
import https from "https";
import querystring from "querystring";

Since you have "type": "module", ES6 modules are enabled. You should change index.js to

import * as OneSignal from '@onesignal/node-onesignal';

export const handler = async (event) => {
    const response = "hey";
    console.log("testing")

    return response;
};

And, if you want a default export, use:

import * as OneSignal from '@onesignal/node-onesignal';
const handler = async (event) => {
    const response = "hey";
    console.log("testing")

    return response;
};

export default handler

Since you are using the app and org keys in your serverless.yml file, its using Serverless Dashboard plugin for deployment.

Unfortunately, this plugin doesn't have an ESM support and hence is using require() statements.

At the moment, there is no plan to support ESM in Serverless Dashboard. Refer: https://github.com/serverless/dashboard-plugin/issues/564

So you have a couple of options:

1. Remove Serverless Dashboard (since its already deprecated). You can do this by removing the app and org keys from your serverless.yml file.
2. Migrate from Serverless Dashboard to Serverless Console, which already supports ES Modules.
3. Rewrite your application logic using CommonJS (instead of ES Modules).