Function IsOnlyTimezoneShift

Checks if two dates differ only by a timezone-like shift. Returns true if the difference is EXACTLY a whole number of hours (no variance in minutes/seconds/milliseconds) and within 23 hours. This helps detect timezone interpretation issues with datetime/datetime2 fields that don't store timezone information.

Example

// 6-hour timezone shift - returns true
IsOnlyTimezoneShift(new Date('2025-12-25T10:30:45.123Z'), new Date('2025-12-25T16:30:45.123Z'));
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Example

// Different by 1ms - returns false (real change)
IsOnlyTimezoneShift(new Date('2025-12-25T10:30:45.123Z'), new Date('2025-12-25T16:30:45.124Z'));
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