تحويل طابع Unix الزمني.

Dates must be valid; date input is UTC. Leap seconds are not represented.

Unix timestamps count elapsed time since 1970-01-01 at UTC. Millisecond values are one thousand times second values. Stating UTC avoids local-zone ambiguity; daylight saving does not alter the timestamp itself.

0 Unix seconds → 1970-01-01T00:00:00.000Z.