URLSearchParams: keys is not a function

[DomenicoCasillo]

Bug Report

What

URLSearchParams polyfill (v3) seems to be incomplete in Firefox 37 Desktop.

Details

const urlParams = new URLSearchParams(location.search);
console.log(urlParams.keys());

The urlParams object is correctly created but on the second line, an error is triggered with
TypeError: urlParams.keys is not a function

Browser: Firefox 37 Desktop (Mozilla/5.0 (Windows NT 6.1; rv:37.0) Gecko/20100101 Firefox/37.0)
Device: Desktop
Polyfill URL: https://polyfill.io/v3/polyfill.min.js?features=Promise.prototype.finally%2CPromise%2CURLSearchParams%2CArray.prototype.flatMap

[JakeChampion]

@DomenicoCasillo, thanks for the issue, could you please post the full polyfill.io url you are using and the full user-agent of the browser which is seeing the issue please? With that information we should hopefully be able to find the cause of the problem

[DomenicoCasillo]

@DomenicoCasillo, thanks for the issue, could you please post the full polyfill.io url you are using and the full user-agent of the browser which is seeing the issue please? With that information we should hopefully be able to find the cause of the problem

I've updated the initial post with additional details. I can add that even entries and values are not available.

[JakeChampion]

Thanks @DomenicoCasillo - I have confirmed the issue now 👍

This is happening because the polyfill has not been applied, you can see that if you run URLSearchParams.toString(), it will return this:

"function URLSearchParams() {
    [native code]
}"

That is happening because Firefox 37 passes all the checks in this section of code:
https://github.com/Financial-Times/polyfill-library/blob/2cfa74e454bf6736234bad9bdeca5d96d451ebc2/polyfills/URL/polyfill.js#L36-L45

We need to update that section of code to check for the methods you've mentioned: keys, values, entries.

If you submit a pull-request which does that, I'm happy to review it 👍

[romainmenke]

Bit of a rabbit hole :)

One of the reasons it is not working as expected is because there are a few missing dependencies and Array.from also seems to be needed in more browser versions than currently stated.

I'll take a look and patch the needed pieces.
Also adding tests from WPT to have extra coverage.

---

Update : Array.from itself seems fine.