|
| 1 | +export const metadata = { |
| 2 | + title: `Unexpected token 'export' Error`, |
| 3 | +} |
| 4 | + |
| 5 | +# {metadata.title} |
| 6 | + |
| 7 | +You may run into the following error when you run migrations or start the Medusa application from the `.medusa/server` directory, such as during deployment: |
| 8 | + |
| 9 | +```bash |
| 10 | +SyntaxError: Unexpected token 'export' |
| 11 | +``` |
| 12 | + |
| 13 | +The error points to a compiled JavaScript file in the `.medusa/server` directory, such as `.medusa/server/medusa-config.js` or a file under `.medusa/server/src`. |
| 14 | + |
| 15 | +## Why this Error Occurred |
| 16 | + |
| 17 | +The Medusa application loads your files, including the configuration file, migrations, API routes, and subscribers, as CommonJS modules at runtime. |
| 18 | + |
| 19 | +The [build](!docs!/learn/build) command compiles your TypeScript files using the `module` option in your `tsconfig.json` file. If you set that option to an ES module format, such as `ESNext` or `ES2022`, the compiled files keep the `export` and `import` keywords instead of using CommonJS syntax. |
| 20 | + |
| 21 | +Node.js then treats every `.js` file as CommonJS, since the `package.json` file of a Medusa application doesn't have a `"type": "module"` field. So, Node.js fails to parse the `export` keyword and throws the above error. |
| 22 | + |
| 23 | +--- |
| 24 | + |
| 25 | +## How to Diagnose it |
| 26 | + |
| 27 | +1. Open the `tsconfig.json` file at the root of your Medusa application and check the `module` and `moduleResolution` options. An ES module format, such as `ESNext`, `ES2020`, or `ES2022`, causes this error. |
| 28 | +2. Open the `package.json` file at the root of your Medusa application and check whether it has a `"type": "module"` field. If it does, remove it using the steps in the next section. |
| 29 | +3. Open the file mentioned in the error message under `.medusa/server` and check whether it starts with `import` or contains `export` statements. If it does, the compiled output uses an ES module format. |
| 30 | + |
| 31 | +--- |
| 32 | + |
| 33 | +## How to Fix it |
| 34 | + |
| 35 | +To fix this error, change the `module` and `moduleResolution` options in your `tsconfig.json` file to `Node16`, which is the configuration that Medusa applications use: |
| 36 | + |
| 37 | +```json title="tsconfig.json" |
| 38 | +{ |
| 39 | + "compilerOptions": { |
| 40 | + "module": "Node16", |
| 41 | + "moduleResolution": "Node16" |
| 42 | + } |
| 43 | +} |
| 44 | +``` |
| 45 | + |
| 46 | +Then, if your `package.json` file has a `"type": "module"` field, remove it: |
| 47 | + |
| 48 | +```json title="package.json" |
| 49 | +{ |
| 50 | + "type": "module" |
| 51 | +} |
| 52 | +``` |
| 53 | + |
| 54 | +<Note type="warning"> |
| 55 | + |
| 56 | +Don't add a `"type": "module"` field to your `package.json` file to resolve this error. It changes how Node.js interprets every file in your project, and Medusa applications don't support ES modules. Learn more about this field in the [Node.js documentation](https://nodejs.org/api/packages.html#type). |
| 57 | + |
| 58 | +</Note> |
| 59 | + |
| 60 | +Finally, create the production build again: |
| 61 | + |
| 62 | +```bash npx2yarn |
| 63 | +npx medusa build |
| 64 | +``` |
| 65 | + |
| 66 | +The compiled files now use CommonJS syntax, and you can run migrations and start the application as explained in the [build](!docs!/learn/build) documentation. |
| 67 | + |
| 68 | +--- |
| 69 | + |
| 70 | +## Additional Resources |
| 71 | + |
| 72 | +- [Build Medusa Application](!docs!/learn/build): Learn how to create a production build and start it. |
| 73 | +- [General Deployment](!docs!/learn/deployment/general): Learn the general steps to deploy a Medusa application. |
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