What is the signature for a custom route handler?

Library Affected: https://developers.google.com/web/tools/workbox/modules/workbox-routing#matching_and_handling_in_routes

Issue or Feature Request Description: The handler callback method in the docs has the following signature:

const handlerCb = ({url, event, params})

But the handle method in all of the workbox strategies seems to have the following signature;

async handle({ event, request }) 

I see from the debugger that the object passed to the handle method has the following properties:

{
   url: URL, 
   request: Request, 
   event: FetchEvent, 
   params: undefined
}

Could these docs be updated? Or could they point to the API docs for Workbox? (Sorry. I am a java programmer struggling to adjust to this crazy javascript stuff.)

[philipwalton]

But the handle method in all of the workbox strategies seems to have the following signature;

async handle({ event, request }) 

@daffinm note that, in JavaScript, you generally only list the parameters a given method is using—not all the parameters it’s invoked with.

In the case of Workbox strategies, they all only use the request and event params, but since Workbox’s routing interface accepts handlers that may also use url and/or params, every invocation of a handler function (which all strategy classes handle() method is) from a Router object needs to be invoked with all four object params, even if the function doesn’t end up using them.

[jeffposnick]

The relevant TypeScript definitions are at https://github.com/GoogleChrome/workbox/blob/3ac095656354157eb4b58c93d3b1e390a5ba34dd/packages/workbox-core/src/types.ts#L36-L56

Ultimately, that’s the intended “source of truth”.

I’m not sure which docs you were looking at, but if anything doesn’t match that (which is unfortunately possible; our docs are generated from JSDocs, not the TypeScript signature) then it’s an issue with the docs that we’ll resolve.

https://developers.google.com/web/tools/workbox/reference-docs/latest/module-workbox-routing#~handlerCallback is the “official” docs—is that what you were looking at? If not, what’s the URL of the page?