content: [API Reference](https://react.dev/reference/react)
  
  [APIs](https://react.dev/reference/react-dom)
  
  # preinitModule[Link for this heading]()
  
  ### Note
  
  [React-based frameworks](https://react.dev/learn/start-a-new-react-project) frequently handle resource loading for you, so you might not have to call this API yourself. Consult your framework’s documentation for details.
  
  `preinitModule` lets you eagerly fetch and evaluate an ESM module.
  
  ```
  
  preinitModule("https://example.com/module.js", {as: "script"});
  ```
  
  - [Reference]()
    
    - [`preinitModule(href, options)`]()
  - [Usage]()
    
    - [Preloading when rendering]()
    - [Preloading in an event handler]()
  
  * * *
  
  ## Reference[Link for Reference]()
  
  ### `preinitModule(href, options)`[Link for this heading]()
  
  To preinit an ESM module, call the `preinitModule` function from `react-dom`.
  
  ```
  
  import { preinitModule } from 'react-dom';
  
  
  
  function AppRoot() {
  
    preinitModule("https://example.com/module.js", {as: "script"});
  
    // ...
  
  }
  ```
  
  [See more examples below.]()
  
  The `preinitModule` function provides the browser with a hint that it should start downloading and executing the given module, which can save time. Modules that you `preinit` are executed when they finish downloading.
  
  #### Parameters[Link for Parameters]()
  
  - `href`: a string. The URL of the module you want to download and execute.
  - `options`: an object. It contains the following properties:
    
    - `as`: a required string. It must be `'script'`.
    - `crossOrigin`: a string. The [CORS policy](https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/crossorigin) to use. Its possible values are `anonymous` and `use-credentials`.
    - `integrity`: a string. A cryptographic hash of the module, to [verify its authenticity](https://developer.mozilla.org/en-US/docs/Web/Security/Subresource_Integrity).
    - `nonce`: a string. A cryptographic [nonce to allow the module](https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/nonce) when using a strict Content Security Policy.
  
  #### Returns[Link for Returns]()
  
  `preinitModule` returns nothing.
  
  #### Caveats[Link for Caveats]()
  
  - Multiple calls to `preinitModule` with the same `href` have the same effect as a single call.
  - In the browser, you can call `preinitModule` in any situation: while rendering a component, in an Effect, in an event handler, and so on.
  - In server-side rendering or when rendering Server Components, `preinitModule` only has an effect if you call it while rendering a component or in an async context originating from rendering a component. Any other calls will be ignored.
  
  * * *
  
  ## Usage[Link for Usage]()
  
  ### Preloading when rendering[Link for Preloading when rendering]()
  
  Call `preinitModule` when rendering a component if you know that it or its children will use a specific module and you’re OK with the module being evaluated and thereby taking effect immediately upon being downloaded.
  
  ```
  
  import { preinitModule } from 'react-dom';
  
  
  
  function AppRoot() {
  
    preinitModule("https://example.com/module.js", {as: "script"});
  
    return ...;
  
  }
  ```
  
  If you want the browser to download the module but not to execute it right away, use [`preloadModule`](https://react.dev/reference/react-dom/preloadModule) instead. If you want to preinit a script that isn’t an ESM module, use [`preinit`](https://react.dev/reference/react-dom/preinit).
  
  ### Preloading in an event handler[Link for Preloading in an event handler]()
  
  Call `preinitModule` in an event handler before transitioning to a page or state where the module will be needed. This gets the process started earlier than if you call it during the rendering of the new page or state.
  
  ```
  
  import { preinitModule } from 'react-dom';
  
  
  
  function CallToAction() {
  
    const onClick = () => {
  
      preinitModule("https://example.com/module.js", {as: "script"});
  
      startWizard();
  
    }
  
    return (
  
      <button onClick={onClick}>Start Wizard</button>
  
    );
  
  }
  ```
  
  [Previouspreinit](https://react.dev/reference/react-dom/preinit)
  
  [Nextpreload](https://react.dev/reference/react-dom/preload)