[Fixed] Deploying NodeJS in Render (Web Service) getting " SyntaxError: Unexpected token '??=' " – Node.js

The Problem:

When deploying a Node.js and MongoDB Atlas application to Render (Web Services), the deployment is successful, but the application fails to run, resulting in a "SyntaxError: Unexpected token ‘??=’" error. This error occurs specifically in the ‘find_and_modify.js’ file within the ‘mongodb’ package. The developer has tried searching for a solution but could not find any. They need assistance in fixing this issue to make their online portfolio application functional.

The Solutions:

Solution 1: Add the engines in `package.json`

The error message “SyntaxError: Unexpected token ‘??='” suggests that the Node.js version used by Render is not compatible with the version required by your project. To address this issue, you need to specify the compatible Node.js version in your project’s package.json file.

To do this, follow these steps:

1. Open your project’s package.json file.

2. Add the following engines property to the file:

{
  "engines": {
    "node": ">=14 <18.17.1"
  }
}

3. Save the package.json file.

This will ensure that Render uses the compatible Node.js version for your project, resolving the "SyntaxError: Unexpected token ‘??=’" issue.

Solution 2: Node.js Version Check

Often, the root of this error is using a Node.js syntax feature that is not supported by the Node.js version running in the production environment. The supported syntax can vary across different versions of Node.js. For example, Node.js 15.0.0 introduced the “??=” nullish coalescing operator. If your code uses this operator and your production environment is running an older version of Node.js, you will encounter the error.

1. Determine the Node.js Version in Production:
– Check the documentation for your hosting platform to determine the Node.js version used. In this case, you can find this information in the Render documentation.

2. Inspect Your Code:
– Review the codebase to identify any usage of syntax features that might not be supported in older Node.js versions. Look for features like “??=” or other recent additions.

3. Update Node.js Version in Production:
– If you have identified that the Node.js version in production is older than the version used for development, upgrade the Node.js version in the production environment. This can often be done through the configuration settings or scripts provided by your hosting platform.

4. Redeploy the Application:
– Once you have updated the Node.js version, redeploy your application to the production environment. This ensures that the updated code is executed with the correct version of Node.js.

Solution 3: Specify an older version of MongoDB driver

The error could be caused by an outdated version of the MongoDB driver. Try changing the version of the MongoDB driver in your package.json file to an older version, such as ^4.16.0, like so:

{
  "name": "my-app",
  "version": "1.0.0",
  "description": "My awesome Node.js app",
  "main": "index.js",
  "scripts": {
    "start": "node index.js"
  },
  "dependencies": {
    "mongodb": "^4.16.0"
  }
}

This will install an older version of the MongoDB driver that is compatible with the version of Node.js that you are using. Once you have changed the version in your package.json file, run npm install to install the new version of the MongoDB driver.

Video Explanation: