getLoadContext

The getLoadContext function is another handler within the entry service worker that allows you to create a global context object for the worker thread.

The output of this function is what determines what your context object would look anywhere within the various worker APIs that utilizes it. It takes in the fetch event object as its lone argument and should return an object.

The context object by default, contains the following:

• event: The fetch event object that triggered the worker.
• fetchFromServer: A function utility that allows you to fetch the request (forward the request to the server).

If no getLoadContext function is provided or is defined, but an empty object ({}) is returned, the default context object would be used.

In the other case where a non-empty object is returned, the default context object would be merged with the object returned by the getLoadContext function.

Here's an example of how you can use the getLoadContext function:

export const getLoadContext = (event: FetchEvent) => {
  return {
    unStrippedRequest: event.request,
    fetchFromServer: async (request: Request) => {
      return await fetch(request)
    }
  }
}

In this example, we override the fetchFromServer property of the default context object with a custom function that more or less does the same thing. And we also provided a new property unStrippedRequest that contains the original request object. The context object now available globally within the worker thread would now contain three properties: event, fetchFromServer, and unStrippedRequest.

This can be extended to share cache objects, stores, or any other data you might want to share globally between your workers in your routes and the entry service worker.