1738220 - Collapsible section with details about the brand is not displayed at fastcompany.com with ETP set to STRICT

Status: RESOLVED FIXED

(Core :: Privacy: Anti-Tracking, defect, P3)

Description

[Raul Bucata]

Attachment: 2021-10-28_12-36.png

"Environment:
Operating system: Ubuntu 20.4 LTS x64
Firefox version: :Firefox Nightly 94.0a1 (2021-10-27) (64-bit)

Preconditions:
ETP set to STRICT
Clean profile

Steps to reproduce:

1. Navigate to :https://www.fastcompany.com/brands-that-matter/2021
2. Scroll the page
3. Left-Click on any brand displayed
4. Observe the result

Expected Behavior:
A collapsible section with details about the brand is displayed

Actual Behavior:
Nothing happens

Notes:

• Not reproducible with ETP set to STANDARD
• Works as expected using Chrome
• Screenshot attached

Comment 1

[Thomas Wisniewski [:twisniewski]]

When I click on a brand in strict mode, I see an error in the web console:

Uncaught TypeError: l.get(...).forEach is not a function
    C https://assets.fastcompany.com/_/fc/bundle/js/35.5cf26138880d726a4d0c.js:1
    d https://assets.fastcompany.com/_/fc/bundle/js/vendor.5cf26138880d726a4d0c.js:1
    // snip for brevity

That's in this code:

        n.classList.contains('active') ? _(n) : ((0, l.get) (n, 'parentElement.children', [
        ]).forEach(function (e) {
          _(e)
        })

Unfortunately there are a ton of trackers to work through to figure out which is the right one providing this specific forEach function, or otherwise causing the error, so we'll have to do a more thorough diagnosis here.

Comment 2

[Thomas Wisniewski [:twisniewski]]

Ah, the blocked script https://secure.cdn.fastclick.net/js/cnvr-launcher/latest/launcher-stub.min.js is the culprit. It bundes several nodeJS modules, including packages/core-js/internals/dom-iterables.js, which defines the missing forEach method on HTMLCollection the site expects here. We can easily shim this, although it's hard to tell whether it's worth bundling all of the modules or just dom-iterables, so I'll start with that one. I'll upload a SmartBlock patch ASAP.

Comment 3

[Thomas Wisniewski [:twisniewski]]

This was fixed in the Firefox 104 webcompat update in bug 1776673.

Comment 4

[Raul Bucata]

I can confirm the fix.

Tested with:

Browser / Version:Firefox Nightly 105.0a1 (2022-08-15) (64-bit)
Operating System: Windows 10 PRO x64
Operating System: Ubuntu 20.4 LTS x64