One of the most common headaches for JavaScript developers is encountering the dreaded SyntaxError: cannot use import statement outside a module. This error usually happens when Node.js tries to interpret ES module syntax (import/export) in a project that isn’t configured to handle it. By default, Node.js treats .js files as CommonJS modules, so using import without the right setup triggers this syntax error.

The simplest way to fix this is by updating your package.json to include "type": "module". This tells Node.js to treat .js files as ES modules, allowing the use of import and export syntax seamlessly. Alternatively, you can rename your files with the .mjs extension, which Node.js also interprets as ES modules.

If you’re working in a mixed environment with both ES modules and CommonJS, another approach is to stick to require and module.exports for compatibility. Tools like Babel can also help transpile modern JavaScript into a Node.js-compatible format, which is especially useful if you want to use advanced syntax features without breaking older setups.

For developers testing APIs or backend functionality, integrating tools like Keploy can be a game-changer. Keploy can automatically capture API calls and generate test cases, helping you validate functionality without worrying about module configuration issues breaking your tests.

Other tips include checking your Node.js version, as older versions don’t fully support ES modules, and ensuring your code isn’t being run directly in environments like older browser-targeted setups without proper bundling.

Ultimately, resolving the syntaxerror cannot use import statement outside a module boils down to correctly configuring your project environment and understanding the distinction between CommonJS and ES modules. With the right setup, Node.js projects can leverage modern JavaScript syntax effortlessly, and tools like Keploy can further streamline testing and development. Proper configuration ensures fewer runtime errors, smoother debugging, and a cleaner, maintainable codebase.
https://keploy.io/blog/community/cannot-use-import-statement-outside-a-module