Automatically update `.wxt/types/paths.d.ts` and `web_accessible_resources` manifest for favicon

[ImSingee]

Feature Request

For favicon feature: https://developer.chrome.com/docs/extensions/how-to/ui/favicons

Currently, if we want to use this, we have to do following steps:

1. Update permissions in wxt.config.ts to include favicon
2. Update web_accessible_resources in manifest to allow _favicon/*
3. We have to add @ts-ignore or @ts-expect-error when requesting favicon url (since it's not allowed by .wxt/types/paths.d.ts)

function getFaviconUrl(url: string, size = 16) {
  //@ts-expect-error not supported by wxt now
  const u = new URL(browser.runtime.getURL("/_favicon/"));
  u.searchParams.set("pageUrl", url);
  u.searchParams.set("size", size.toString());
  return u.toString();
}

I expect to use this feature as easily as just adding the favicon permission.

Is your feature request related to a bug?

N/A

What are the alternatives?

N/A

Additional context

N/A

[aklinker1]

This would be a good first issue for anyone looking to contribute.

Here is where we generate the PublicPath type used in browser.runtime.getURL:

https://github.com/wxt-dev/wxt/blob/main/packages%2Fwxt%2Fsrc%2Fcore%2Fgenerate-wxt-dir.ts#L65-L106

Should be as simple as checking wxt.config.manifest.permissions?.includes('favicon') and concatenating a path on for accessing favicons, like \_favicon/${string}.

Then to change the manifest generation, we need to update:

https://github.com/wxt-dev/wxt/blob/main/packages%2Fwxt%2Fsrc%2Fcore%2Futils%2Fmanifest.ts#L50

However, instead of splitting that code apart into those two locations, what we should do is put this in a single file, a WXT module! This would be the second module built into WXT:

https://github.com/wxt-dev/wxt/tree/main/packages%2Fwxt%2Fsrc%2Fbuiltin-modules

Then all we have to do is add two hooks for prepare:publicPaths and manifest:generated with the same logic mentioned above.

We'll also need tests for this, but unit tests would be simple to write for a module! You just need to call the hooks and it's a simple input-output test.

[aklinker1]

Some discussions on the PR, mentioning them here for clarity:

Not every extension that uses the favicon permission needs a web_acccessible_resources entry added - you only need that to use favicons in content scripts. If someone needs access to favicons in a content script, they should add the entry themselves.
– #1570 (review)

So basically we're only gonna add the type for browser.runtime.getURL, WXT won't be adding anything to the web_accessible_resources.