Issue with the URLSearchParams interface in content scripts

Add-ons Development
1

I noticed an issue when working with the [URLSearchParams](https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams) interface in the content script. I am trying to get hold of the keys in the “search” part of a URL.

This works when I try on the browser’s JS console. But when I do the same in the content script’s console, I get an error saying TypeError: obj.searchParams.keys(...) is not iterable.

See outputs below:

obj = new window.URL("https://www.somwebsite.com/show/3001C?name=asd")
keys = [...obj.searchParams.keys()]
// On a regular browser console => Array [ "name" ] 
// On content script's console => TypeError: obj.searchParams.keys(...) is not iterable

Are there limitations on the URL and related APIs in the content script?

BTW, this works just fine on Chrome.

2

window.URL will use the URL constructor from the webpage, which should in theory be just as fine (since it’s X-Ray wrapped). However I wonder if something about the X-Ray wrapper breaks in this case. You should only need to use window.URL over URL if you want to pass the instance back to the page somehow.
See also

3

Thanks for the quick response @freaktechnik. I don’t need to pass anything back to the page script. All I need is get hold of the URL of the current page, extract the search params and take a decision based on the presence of a certain param.

4

Right, so what I’m suggesting is to try and use just new URL instead of new window.URL.

5

Ah, got it. Yeah I tried that too - no change :neutral_face:

6

Then I have two more suspicions:

  1. it’s a bug with a polyfill you’re inadvertently injecting with your content script
  2. it’s a bug in Firefox, and thus you should be able to make a minimal extension (essentially just a content script) that reproduces the bug. If that is the case, please open a bug at https://bugzilla.mozilla.org/enter_bug.cgi?product=WebExtensions&component=Untriaged with that sample extension as attachment.
7

Makes sense, I’ll check that out.