Twenty Seventeen: "undefined is not an object" in JS detection

[domainsupport]

Hello,

We have noticed that when using Twenty Seventeen in Safari the following error is displayed in the console ...

TypeError: undefined is not an object (evaluating 'r["@context"].toLowerCase')

... relating to the JavaScript detection in the header ...

    <script>
    (function(html) {
        html.className = html.className.replace(/\bno-js\b/, 'js')
    })(document.documentElement);
    </script>

This is only shown when you are signed in.

You can actually see this on the Twenty Seventeen theme page here (when signed in to wordpress.org) ... ​https://en-gb.wordpress.org/themes/twentyseventeen/

Just sign in, visit that page with Safari and inspect the console for errors!

Oliver

[domainsupport]

Actually, looks like the error appears whether you're signed in or not but it seems to be shown only in Safari (not in Chrome, Firefox or Opera).

Oliver

[sabernhardt]

Thanks for the report!

This will need testing in Safari for multiple themes.

Three default themes use the same script to replace the class on html:

• Twenty Fifteen
• Twenty Sixteen
• Twenty Seventeen

Twenty Twenty similarly replaces the no-js class, but not in the same way.
Twenty Twenty-One just removes no-js from the (body) class list.

[domainsupport]

Apologies. It looks like this is a ​bug in Safari that is referencing the theme inline script as the source erroneously in the console.

The true cause would appear to be arrays within schema json.

Oliver

[sabernhardt]

Thanks for the follow-up!