@burglekitt/gmt/dist/zoned/compare/isInDaylightSaving.d.ts

Temporal-based date and time utilities with timezone support and polyfill integration

/**
 * Check whether a zoned value's instant falls within daylight saving time.
 *
 * - The third DST-related function in the roadmap, and distinct from the
 *   other two — see docs/dst-disambiguation.md for the full four-way split:
 *   `hasDaylightSaving(timeZone)` asks whether a zone observes DST *at all*
 *   (zone-level, no instant); `listDstTransitions(timeZone, year)` asks
 *   *where* a zone's transitions fall (enumerates instants);
 *   `isInDaylightSaving(value)` asks whether *this particular instant* is
 *   currently in DST. `disambiguation`/`offset` (Group C) are a fourth,
 *   orthogonal concern: what to do when construction lands on an ambiguous
 *   or nonexistent instant.
 * - Returns false for invalid input, and false for a zone that doesn't
 *   observe DST at all.
 *
 * @param value zoned ISO 8601 datetime string
 * @returns true if the instant is in daylight saving time, false otherwise or on invalid input
 *
 * @example isInDaylightSaving("2024-07-15T12:00:00-04:00[America/New_York]") // true
 * @example isInDaylightSaving("2024-01-15T12:00:00-05:00[America/New_York]") // false
 * @example isInDaylightSaving("2024-01-15T12:00:00+11:00[Australia/Sydney]") // true (southern-hemisphere summer)
 * @example isInDaylightSaving("2024-07-15T12:00:00+09:00[Asia/Tokyo]") // false (Asia/Tokyo has no DST)
 * @example isInDaylightSaving("invalid") // false
 */
export declare function isInDaylightSaving(value: string): boolean;