| 1 | // scheduleIdleTask — requestIdleCallback with a setTimeout fallback for |
| 2 | // engines/tests without it. Used for non-urgent rendering work (deferred |
| 3 | // syntax highlighting, progressive markdown block mounting). |
| 4 | |
| 5 | type IdleWindow = Window & { |
| 6 | requestIdleCallback?: (callback: () => void, options?: { timeout: number }) => number; |
| 7 | cancelIdleCallback?: (handle: number) => void; |
| 8 | }; |
| 9 | |
| 10 | export function scheduleIdleTask(callback: () => void, timeoutMs = 1_000): () => void { |
| 11 | const idleWindow = window as IdleWindow; |
| 12 | if (idleWindow.requestIdleCallback) { |
| 13 | const handle = idleWindow.requestIdleCallback(callback, { timeout: timeoutMs }); |
| 14 | return () => idleWindow.cancelIdleCallback?.(handle); |
| 15 | } |
| 16 | const timer = window.setTimeout(callback, Math.min(timeoutMs, 200)); |
| 17 | return () => window.clearTimeout(timer); |
| 18 | } |
| 19 |