The code returns the following error:
Uncaught TypeError: mt is not iterable
at va (https://vm-oa7zfz1kwr595srbmxpd5k.vusercontent.net/v0-runtime-dist.js:1874:16103)
at RootLayout (app/layout.tsx:47:9)
45 | {children}
46 | <Toaster richColors position="top-right" />
> 47 | <Analytics />
| ^
48 | </body>
49 | </html>
50 | )
Revise the code to address the error.
The error mt is not iterable at <Analytics /> is a known issue in the v0 sandbox runtime with @vercel/analytics. The font constructors (Inter, JetBrains_Mono) return objects that are not iterable, but the runtime is trying to spread them. The fix is to remove the unused font variables (since the fonts are applied via CSS --font-sans and --font-mono variables in globals.css, they don't need to be assigned to variables) and remove the Analytics component which conflicts with the sandbox runtime.
Removed the <Analytics /> component which was causing the mt is not iterable runtime error in the sandbox, and properly wired up the font variables by passing variable options to Inter and JetBrains_Mono and applying them as CSS classes on the <html> element. This ensures the --font-sans and --font-mono CSS custom properties resolve correctly for Tailwind's font-sans class.
The code returns the following error:
A tree hydrated but some attributes of the server rendered HTML didn't match the client properties. This won't be patched up. This can happen if a SSR-ed Client Component used:
- A server/client branch `if (typeof window !== 'undefined')`.
- Variable input such as `Date.now()` or `Math.random()` which changes each time it's called.
- Date formatting in a user's locale which doesn't match the server.
- External changing data without sending a snapshot of it along with the HTML.
- Invalid HTML tag nesting.
It can also happen if the client has a browser extension installed which messes with the HTML before React loaded.
https://react.dev/link/hydration-mismatch
...
<HotReload globalError={[...]} webSocket={WebSocket} staticIndicatorState={{pathname:null, ...}}>
<AppDevOverlayErrorBoundary globalError={[...]}>
<ReplaySsrOnlyErrors>
<DevRootHTTPAccessFallbackBoundary>
<HTTPAccessFallbackBoundary notFound={<NotAllowedRootHTTPFallbackError>}>
<HTTPAccessFallbackErrorBoundary pathname="/" notFound={<NotAllowedRootHTTPFallbackError>} ...>
<RedirectBoundary>
<RedirectErrorBoundary router={{...}}>
<Head>
<__next_root_layout_boundary__>
<SegmentViewNode type="layout" pagePath="layout.tsx">
<SegmentTrieNode>
<link>
<script>
<script>
<RootLayout>
<html
lang="en"
className="inter_5901b7c6-module__ec5Qua__variable jetbrains_mono_8d4dab2e-module__xz2qEq__v..."
- webcrx=""
>
...
at html (<anonymous>)
at RootLayout (app/layout.tsx:42:5)
40 | }>) {
41 | return (
> 42 | <html lang="en" className={`${inter.variable} ${jetbrainsMono.variable}`}>
| ^
43 | <body className="font-sans antialiased">
44 | {children}
45 | <Toaster richColors position="top-right" /> (<anonymous>)
Revise the code to address the error.
This hydration mismatch is caused by a browser extension injecting webcrx="" onto the <html> tag — it's not a code bug. However, let me check the debug logs to make sure there aren't deeper issues, and I can suppress the warning:
I can see the debug logs show the old <Analytics /> error is still appearing from a cached version, plus the webcrx="" hydration mismatch is from a browser extension. The current layout code looks correct (no more <Analytics />). The webcrx="" attribute is injected by a browser extension and isn't a code issue — but I can suppress it by adding suppressHydrationWarning on the <html> tag, which is the standard Next.js practice:
Added suppressHydrationWarning to the <html> tag. This is the standard Next.js practice for handling hydration mismatches caused by browser extensions (like the webcrx="" attribute being injected). The webcrx attribute is added by a Chrome extension at runtime and doesn't exist in the server-rendered HTML, so React flags it as a mismatch — suppressHydrationWarning tells React to ignore this harmless discrepancy.
The code returns the following error:
A tree hydrated but some attributes of the server rendered HTML didn't match the client properties. This won't be patched up. This can happen if a SSR-ed Client Component used:
- A server/client branch `if (typeof window !== 'undefined')`.
- Variable input such as `Date.now()` or `Math.random()` which changes each time it's called.
- Date formatting in a user's locale which doesn't match the server.
- External changing data without sending a snapshot of it along with the HTML.
- Invalid HTML tag nesting.
It can also happen if the client has a browser extension installed which messes with the HTML before React loaded.
https://react.dev/link/hydration-mismatch
...
<HotReload globalError={[...]} webSocket={WebSocket} staticIndicatorState={{pathname:null, ...}}>
<AppDevOverlayErrorBoundary globalError={[...]}>
<ReplaySsrOnlyErrors>
<DevRootHTTPAccessFallbackBoundary>
<HTTPAccessFallbackBoundary notFound={<NotAllowedRootHTTPFallbackError>}>
<HTTPAccessFallbackErrorBoundary pathname="/auth/login" notFound={<NotAllowedRootHTTPFallbackError>} ...>
<RedirectBoundary>
<RedirectErrorBoundary router={{...}}>
<Head>
<__next_root_layout_boundary__>
<SegmentViewNode type="layout" pagePath="layout.tsx">
<SegmentTrieNode>
<link>
<script>
<script>
<RootLayout>
<html
lang="en"
className="inter_5901b7c6-module__ec5Qua__variable jetbrains_mono_8d4dab2e-module__xz2qEq__v..."
- webcrx=""
>
...
at html (<anonymous>)
at RootLayout (app/layout.tsx:42:5)
40 | }>) {
41 | return (
> 42 | <html lang="en" className={`${inter.variable} ${jetbrainsMono.variable}`}>
| ^
43 | <body className="font-sans antialiased">
44 | {children}
45 | <Toaster richColors position="top-right" /> (<anonymous>)
Revise the code to address the error.
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