Regex works in Node.js but not in Bun

[SamyPesse]

What version of Bun is running?

1.2.4+fd9a5ea66

What platform is your computer?

Darwin 24.3.0 arm64 arm

What steps can reproduce the bug?

Run the following code using node and bun, you can observe that Node.js returns a result for the regex, while in bun, it logs null:

(async () => {
    const res = await fetch('https://raw.githubusercontent.com/GitbookIO/integrations/c26e594ca86bc75eaa18c4cda995dab56e21008a/integrations/arcade/assets/arcade-preview.png');
    const content = await res.arrayBuffer();
    const base64 = Buffer.from(content).toString('base64');

    const byteRegexp = /^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$/;

    console.log(base64.match(byteRegexp));
})()

This regex might not be correct, but it should still return the same value.

What is the expected behavior?

Both Node.js and Bun should return the same results.

What do you see instead?

Bun returns null.

Additional information

No response

[RiskyMH]

regressed in bun v1.2.3, likely JSC issue

[Jarred-Sumner]

Tracking this in https://bugs.webkit.org/show_bug.cgi?id=289330