Error Reproduction

Production build of Next.js app throws error during client render when using SWC minifier.

Steps

1. Build project using npm run build.
2. Start test server using npm run start.
3. Open page on http://localhost:3000.
4. View browser console output.

Error in browser console:

ReferenceError: e is not defined
    at Object.jU (848-7d911d46e30bd3f0.js:16:18331)
    at new k (848-7d911d46e30bd3f0.js:16:7592)
    at 9705 (848-7d911d46e30bd3f0.js:16:7777)
    at d (webpack-4b7c5c3f98de81bb.js:1:151)
    at 9393 (page-e76bcc040321554e.js:1:223)
    at Function.d (webpack-4b7c5c3f98de81bb.js:1:151)

Analysis

// Minified code of "node_modules/@sbb-esta/lyne-components/development/core/dom.js"
3712: function(t, o, r) {
        r.d(o, {
            $Q: function() {
                return l
            },
            Ev: function() {
                return i
            },
            e_: function() {
                return s
            },
            jU: function() {
                return e    // <-- ReferenceError: e is not defined
            }
        });
        try {
            "u" > typeof Intl && Intl.v8BreakIterator
        } catch (t) {}
        // This variable "n" (the "isBrowser" function) is what should be returned by "jU" function above
        let n = ()=>"object" == typeof document && !!document
          , s = ()=>n() && document.documentElement.getAttribute("dir") || "ltr";
        function i(t, o, r) {
            r ? t.setAttribute(o, r) : t.removeAttribute(o)
        }

Notice

• Error only occurs when multiple different web components are used in a React component. Therefore the TestComponent uses SbbToggle and SbbButton. Rendering only SbbToggle does not produce the error.
• Error only occurs when using SWC minifier in Next.js build (which is the default). Setting swcMinify: false in next.config.mjs makes the error go away.