23 lines
1005 B
TypeScript
23 lines
1005 B
TypeScript
 
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// Parse an "HH:mm" (24h) string into minutes-since-midnight, or null if malformed.
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export function parseHHMM(value: string): number | null {
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const m = /^(\d{2}):(\d{2})$/.exec(value);
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if (!m) return null;
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const hours = Number(m[1]);
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const minutes = Number(m[2]);
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if (hours > 23 || minutes > 59) return null;
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return hours * 60 + minutes;
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}
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// Is `now`'s wall-clock time inside the [start, end) window? The window may wrap
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// past midnight (start > end, e.g. 21:00 → 07:00). A zero-length window
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// (start === end) is treated as never active. Malformed inputs → false.
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export function isWithinTimeWindow(start: string, end: string, now: Date = new Date()): boolean {
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const s = parseHHMM(start);
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const e = parseHHMM(end);
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if (s === null || e === null || s === e) return false;
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const cur = now.getHours() * 60 + now.getMinutes();
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if (s < e) return cur >= s && cur < e;
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// Overnight wrap: active from start until midnight, then midnight until end.
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return cur >= s || cur < e;
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}
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