SyntaxError: Unexpected token ':' in TypeScript file using Next.js

SyntaxError: Unexpected token ‘:’ in TypeScript file using Next.js

If you are encountering a SyntaxError: Unexpected token ':' in your TypeScript file while using Next.js, don’t worry, you are not alone. This error is usually caused by a mismatch between the version of TypeScript you are using and the version supported by Next.js.

To resolve this issue, you have a few different options:

Option 1: Update TypeScript

The first solution is to update your TypeScript version to match the one supported by Next.js. This will ensure that the syntax used in your TypeScript file is compatible with the Next.js framework.

To update TypeScript, you can run the following command in your project’s root directory:

npm install typescript@latest

Once TypeScript is updated, you can restart your development server and the error should be resolved.

Option 2: Downgrade Next.js

If updating TypeScript is not an option for your project, you can consider downgrading your Next.js version to match the TypeScript version you are using. This will allow you to continue using the syntax that is supported by your current TypeScript version.

To downgrade Next.js, you can run the following command in your project’s root directory:

npm install next@{version}

Replace {version} with the specific version number you want to downgrade to. For example, if you are using Next.js version 12.0.1, you can run:

npm install next@12.0.1

After downgrading Next.js, restart your development server and the error should be resolved.

Option 3: Use Babel

If neither updating TypeScript nor downgrading Next.js is feasible for your project, you can try using Babel to transpile your TypeScript code. Babel is a popular JavaScript compiler that can be configured to support the latest syntax features.

To set up Babel with Next.js, follow these steps:

Install the required packages:

npm install --save-dev @babel/preset-typescript @babel/preset-react

Create a .babelrc file in your project’s root directory and add the following configuration:

{
  "presets": ["next/babel", "@babel/preset-typescript"]
}

Update your next.config.js file to use Babel for TypeScript files:

module.exports = {
  // ...
  webpack(config) {
    config.module.rules.push({
      test: /.(ts|tsx)$/,
      use: {
        loader: 'babel-loader',
        options: {
          presets: ['@babel/preset-typescript'],
        },
      },
    });
    return config;
  },
};

After setting up Babel, restart your development server and the error should be resolved.

These are the three main solutions to fix the SyntaxError: Unexpected token ':' in a TypeScript file using Next.js. Choose the solution that best fits your project’s requirements and get back to coding!

If you have any further questions or need additional assistance, feel free to reach out to the Next.js community or consult the official documentation.

SyntaxError: Unexpected token ‘:’ in TypeScript file using Next.js