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Fix browser compatibility: guard requestIdleCallback and startViewTransition #1464

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Merged
N2D4 merged 1 commit into from
May 21, 2026
Merged

Fix browser compatibility: guard requestIdleCallback and startViewTransition #1464

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5 changes: 5 additions & 0 deletions apps/dashboard/src/components/theme-toggle.tsx
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,11 @@ export default function ThemeToggle() {
return;
}

if (typeof document.startViewTransition !== "function") {
setTheme(nextTheme);
return;
}
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@cursor cursor Bot May 21, 2026

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Redundant startViewTransition check duplicates existing guard

Low Severity

The new typeof document.startViewTransition !== "function" check on lines 25-28 is redundant dead code. The existing supportsViewTransitions() function (line 8-10) already checks "startViewTransition" in document, and the early return on line 20 ensures execution only reaches line 25 when that property exists. In all real browser implementations, when "startViewTransition" in document is true, the property is always a function, making this second guard unreachable.

Fix in Cursor Fix in Web

Reviewed by Cursor Bugbot for commit b5232a1. Configure here.

Comment on lines +25 to +28
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@greptile-apps greptile-apps Bot May 21, 2026

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P2 Redundant guard — already covered by supportsViewTransitions()

The new typeof document.startViewTransition !== "function" check is unreachable in practice. The existing supportsViewTransitions() call on line 20 uses "startViewTransition" in document, which already returns false whenever the API is absent, causing an early return before this block is ever evaluated. The only case where this new guard would fire is if startViewTransition is present on document but isn't a function — a scenario that doesn't exist in any real browser. Consider either updating supportsViewTransitions() to use typeof document.startViewTransition === "function" and removing this guard, or simply removing this redundant block.

Prompt To Fix With AI 
This is a comment left during a code review.
Path: apps/dashboard/src/components/theme-toggle.tsx
Line: 25-28

Comment:
**Redundant guard — already covered by `supportsViewTransitions()`**

The new `typeof document.startViewTransition !== "function"` check is unreachable in practice. The existing `supportsViewTransitions()` call on line 20 uses `"startViewTransition" in document`, which already returns `false` whenever the API is absent, causing an early return before this block is ever evaluated. The only case where this new guard would fire is if `startViewTransition` is present on `document` but isn't a function — a scenario that doesn't exist in any real browser. Consider either updating `supportsViewTransitions()` to use `typeof document.startViewTransition === "function"` and removing this guard, or simply removing this redundant block.

How can I resolve this? If you propose a fix, please make it concise.


document.documentElement.classList.add("vt-disable-transitions");

const transition = document.startViewTransition(() => {
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9 changes: 7 additions & 2 deletions apps/dashboard/src/hooks/use-wait-for-idle.tsx
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Original file line number Diff line number Diff line change
Expand Up @@ -5,10 +5,15 @@ export function useWaitForIdle(min = 0, max = 5000) {
useEffect(() => {
let cancelled = false;
setTimeout(() => {
requestIdleCallback(() => {
const cb = () => {
if (cancelled) return;
setHasWaited(true);
}, { timeout: max - min });
};
if (typeof requestIdleCallback === "function") {
requestIdleCallback(cb, { timeout: max - min });
} else {
setTimeout(cb, max - min);
}
Comment on lines +12 to +16
}, min);
return () => {
cancelled = true;
Comment on lines 5 to 19
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