How to Solve the “Cannot use import statement outside a module” Error in React TypeScript

Introduction to the “Cannot use import statement outside a module” Error

When working with React and TypeScript, you may encounter the “Cannot use import statement outside a module” error. This error typically occurs when you try to use the import statement in a file that is not recognized as a module. It can be frustrating, but fortunately, there are solutions to resolve this error and ensure your React TypeScript project runs smoothly.

In this article, we will explore the causes of the “Cannot use import statement outside a module” error and provide step-by-step solutions to fix it.

Understanding the Error Message

What does the error message mean?

The error message “Cannot use import statement outside a module” indicates that the file where you’re using the import statement is not being treated as a module. In TypeScript, modules are used to encapsulate code and provide a way to organize and reuse functionality. When a file is not recognized as a module, the import statement cannot be used.

Solution 1: Convert the File to a Module

Steps to convert the file to a module

To fix the “Cannot use import statement outside a module” error, you can convert the file to a module. Follow these steps:

1. Add the .ts or .tsx extension to the file if it doesn’t have one already.
2. Ensure that the file is located in a directory that TypeScript recognizes as a module. Typically, this means the file should be inside a folder with its own tsconfig.json file.
3. Open the tsconfig.json file in the root directory of your project.
4. Ensure that the module field in the compilerOptions section is set to "esnext" or "commonjs". For example:

{
  "compilerOptions": {
    "module": "esnext"
  }
}

5.Save the changes and restart your development server if necessary.

Solution 2: Use a Build Tool

Use a build tool like Webpack or Rollup

If converting the file to a module doesn’t resolve the issue, you can use a build tool like Webpack or Rollup to bundle your TypeScript files. These build tools handle the module resolution and transformation, allowing you to use import statements without encountering the error.

Here are the general steps to use a build tool:

1. Install Webpack or Rollup in your project:

npm install webpack --save-dev

or

npm install rollup --save-dev

2.Set up the configuration file for the build tool (e.g., webpack.config.js or rollup.config.js).

3.Configure the build tool to handle TypeScript files and perform the necessary module resolution.

4.Run the build command to generate the bundled JavaScript file.

Solution 3: Check Your File Extensions

Ensure the file extensions are correct

Another common cause of the “Cannot use import statement outside a module” error is incorrect file extensions. Make sure that:

• The file you’re trying to import is using the correct file extension (e.g., .ts or .tsx for TypeScript files).
• The file where you’re using the import statement is also using the correct file extension.
• The imported file is located in the correct directory relative to the importing file.

Conclusion

The “Cannot use import statement outside a module” error can be encountered when working with React and TypeScript. By following the solutions outlined in this article, you can resolve this error and ensure that your React TypeScript project functions as expected. Remember to convert your file to a module, use a build tool like Webpack or Rollup, and double-check your file extensions to ensure they are correct. With these steps, you’ll be able to import modules successfully and continue developing your React applications with TypeScript.