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How to Fix SyntaxError: Unexpected Token ‘export’ in JavaScript

Anastasios Antoniadis

Share on X (Twitter) Share on Facebook Share on Pinterest Share on LinkedInWhen developing JavaScript applications, encountering syntax errors is a common part of the debugging process. One such error that developers often come across is SyntaxError: Unexpected token ‘export’. This error can be perplexing, especially for those who are new to working with modules …

Javascript

When developing JavaScript applications, encountering syntax errors is a common part of the debugging process. One such error that developers often come across is SyntaxError: Unexpected token 'export'. This error can be perplexing, especially for those who are new to working with modules in JavaScript. The error typically indicates a problem with how export statements are used or understood in the current JavaScript environment. This article provides an in-depth look at the causes of this error and outlines strategies for resolving it, ensuring a smoother development experience.

Understanding the Error

The SyntaxError: Unexpected token 'export' occurs when the JavaScript engine encounters an export statement that it doesn’t recognize. This can happen for several reasons, primarily related to the use of ECMAScript Modules (ESM) in environments that do not support them or are not configured to handle them correctly.

JavaScript modules allow you to break up your code into separate files, making it more manageable and maintainable. The export statement is used to expose functions, objects, or primitives from a module so they can be used in other modules with the import statement.

Common Causes

  • Incorrect Environment Configuration: The JavaScript runtime or bundler isn’t configured to support ES modules.
  • Running Modules Directly in Browsers: Older browsers do not support ES module syntax, or the <script> tag lacks type="module".
  • Node.js Version Mismatch: Using an older version of Node.js that doesn’t support ES modules natively.
  • File Extension Misconfiguration: For Node.js, using ES modules with .js extension without the proper configuration in package.json.

How to Fix the Error

1. Ensure Environment Supports ES Modules

  • For Node.js: Ensure you’re using Node.js version 12.x or higher, as these versions have stable support for ES modules. Use the .mjs extension for your module files or set "type": "module" in your package.json to treat .js files as ES modules.
  • For browsers: Use modern browsers with ES module support. When including your module script in HTML, specify type="module" in the <script> tag:
<script type="module" src="path/to/your_module.js"></script>

2. Configure Build Tools and Transpilers

If you’re using build tools like Webpack, Babel, or TypeScript, ensure they are configured to handle ES modules:

  • Webpack: Use the latest version and configure your webpack.config.js to use a module-friendly loader for JavaScript files.
  • Babel: Install @babel/plugin-syntax-dynamic-import and @babel/preset-env, and configure your .babelrc or babel.config.js to enable ES module syntax.
  • TypeScript: Set "module": "ESNext" in your tsconfig.json.

3. Use Correct File Extensions and Package Configuration for Node.js

  • When using Node.js, if you prefer to use the .js extension for modules, add "type": "module" in your project’s package.json. This tells Node.js to treat .js files as ES modules.
  • Alternatively, use the .mjs extension for your module files, which Node.js recognizes as ES modules without additional configuration.

4. Update or Polyfill for Older Browsers

  • If supporting older browsers is necessary, use a module bundler like Webpack or Rollup to compile your code into a format compatible with those browsers.
  • Utilize Babel to transpile modern JavaScript to a version compatible with older browsers, ensuring features like export and import are correctly transformed.

5. Debugging and Validation

  • Validate your import and export statements for typos or incorrect paths, as these can also trigger syntax errors.
  • Use linters like ESLint with appropriate configurations to catch syntax issues early in the development process.

Conclusion

The SyntaxError: Unexpected token 'export' in JavaScript is a manageable issue, often stemming from environmental configurations that do not support or are not properly set up for ECMAScript Modules. By ensuring that your development environment, build tools, and browsers are correctly configured to handle ES modules, you can effectively eliminate this error. Additionally, keeping your development tools updated and adhering to best practices for module usage will help prevent similar issues and contribute to a more efficient and error-free development workflow.

Anastasios Antoniadis
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