localStorage hydration mismatch
Review this React TypeScript component (Next.js App Router).
What a strong answer looks like
Separate real bugs from style. Rank issues by severity, point at the root cause rather than the symptom, and suggest a concrete fix, specific and kind.
0:00 of about 24 min
Mark a line and say what kind of problem it is.0 findings
1function ThemeToggle() {
2 const [theme, setTheme] = useState(
3 typeof window !== 'undefined' ? localStorage.getItem('theme') ?? 'light' : 'light'
4 );
5
6 return (
7 <button onClick={() => setTheme(theme === 'light' ? 'dark' : 'light')} className={theme}>
8 Toggle theme
9 </button>
10 );
11}
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