Uncaught SyntaxError: Cannot use import statement outside a module when importing ECMAScript 6

If you are a JavaScript developer working with ECMAScript 6 (ES6) modules, you might have encountered the error message “Uncaught SyntaxError: Cannot use import statement outside a module” at some point. This error occurs when you try to use the import statement to import ES6 modules in a JavaScript file that is not being treated as a module.

To understand this error and how to resolve it, let’s dive into the details.

Understanding the Error

ECMAScript 6 introduced a new module system that allows developers to organize their code into reusable modules. The import statement is used to import functionality from other modules, and the export statement is used to export functionality from a module.

However, in order to use the import statement, the JavaScript file needs to be treated as a module. By default, JavaScript files are treated as scripts, and the import statement is not recognized.

Solutions

There are a few different solutions to resolve the “Uncaught SyntaxError: Cannot use import statement outside a module” error. Let’s explore them one by one:

1. Use the type=”module” attribute

The simplest solution is to add the type=”module” attribute to the script tag that imports the ES6 module. This tells the browser to treat the JavaScript file as a module and enables the use of import statements.

Make sure to replace “your-module.js” with the actual path to your ES6 module file.

2. Use a bundler like Webpack or Rollup

If you are working on a larger project with multiple JavaScript files, using a bundler like Webpack or Rollup is a recommended approach. These bundlers can handle the module system and bundle all your JavaScript files into a single file that can be used in the browser.

Here’s an example of how to use Webpack to bundle your ES6 modules:

// webpack.config.js
const path = require('path');

module.exports = {
    entry: './your-module.js',
    output: {
        filename: 'bundle.js',
        path: path.resolve(__dirname, 'dist'),
    },
};

After configuring Webpack, you can run the bundling process using the following command:

npx webpack

This will generate a bundled JavaScript file (e.g., bundle.js) in the specified output path.

Conclusion

The “Uncaught SyntaxError: Cannot use import statement outside a module” error occurs when you try to use the import statement to import ES6 modules in a JavaScript file that is not being treated as a module. By using the type=”module” attribute or a bundler like Webpack, you can resolve this error and leverage the power of ECMAScript 6 modules in your JavaScript projects.

Remember to choose the solution that best fits your project’s requirements and development workflow.