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# Module Export Syntax

When exporting functions in the following files, we recommend you use the standard export syntax contained in the documentation's code examples:

+ [`events.js`](portalId::bcc88c7b-94f5-4c35-b1cb-d7a20f2669b0resourceId::595cc6cb-bc5d-484b-8f70-fac8a3abae87*fallback::https://dev.wix.com/docs/develop-websites/articles/coding-with-velo/backend-code/web-modules/velo-backend-events)
+ [`data.js`](portalId::bcc88c7b-94f5-4c35-b1cb-d7a20f2669b0resourceId::7843d8ac-d0af-4112-9ba8-f6a81dc9cbb0slug::using-data-hooks*fallback::https://dev.wix.com/docs/develop-websites/articles/databases/wix-data/hooks/using-data-hooks)
+ [`routers.js`](fallback::https://dev.wix.com/docs/develop-websites/articles/coding-with-velo/routers/about-routers)
+ [Service plugin code files](portalId::bcc88c7b-94f5-4c35-b1cb-d7a20f2669b0resourceId::1faa11b0-b2be-4d78-a100-8016cf8b1fb8*fallback::https://dev.wix.com/docs/develop-websites/articles/coding-with-velo/integrations/custom-extensions-spis/custom-app-extensions-using-sp-is)

You can also use other export formats that are part of the [ES6 (ES2015) module export syntax](fallback::https://developer.mozilla.org/en-US/docs/web/javascript/reference/statements/export). However, the following export formats are **not** supported in `events.js`, `data.js`, `routers.js`, or service plugin code files:

+ **Re-exporting a function:** Directly re-exporting a function imported from an npm or Velo package. For example, this **doesn't** work:

  ```javascript
  import { myFunction } from 'myPackage';
  
  export const wixMediaManager_onFileUploaded = myFunction;
  ```

  The following alternative syntax **is** supported:

  ```javascript
  import { myFunction } from 'myPackage';
  
  export const wixMediaManager_onFileUploaded = (paramA, paramB) => myFunction(paramA, paramB);
  ```

+ **Dynamic exports:** Exports including a dynamic operation or expression that requires execution to resolve. For example, this **doesn't** work:

  ```javascript
  import myPackage from 'my-package';
  
  export const myRouter_Router = myPackage.router((paramA, paramB) => {
    // ...
  });
  ```

  The following alternative syntax **is** supported:

  ```javascript
  import myPackage from 'my-package';

  const functionForExport = myPackage.router((paramA, paramB) => {
    // ...
  })

  export const myRouter_Router = (paramA, paramB) => functionForExport(paramA, ParamB);
  ```

+ **Exports wrapped in objects:** Exports where functions are defined as properties of an object. For example, this **doesn't** work:
  
  ```javascript
  const dataHooks = {
    beforeInsert: (paramA, paramB) => {
      // ...
    }
  };

  export const MyCollection_beforeInsert = dataHooks.beforeInsert;
  ```

  The following alternative syntax **is** supported:

  ```javascript
  const dataHooks = {
    beforeInsert: (paramA, paramB) => {
      // ...
    }
  };

  export const MyCollection_beforeInsert = (paramA, paramB) => dataHooks.beforeInsert(paramA, paramB);
  ```

+ **CommonJS exports:** Exports in the CommonJS (CJS) format that preceded ES6 (ES2015). For example, this **doesn't** work:

  ```javascript
  module.exports = {
    MyCollection_beforeInsert: () => {}
  };
  ```

Functions exported using a syntax that isn't supported aren't called by the triggering event.