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Vitest · Method

vi.setSystemTime

vi.setSystemTime sets the clock used by date-related APIs in a test. It helps make time-dependent tests predictable, but it does not run timers.

Last updated 2 November 2026

Syntax

function setSystemTime(date: string | number | Date | Temporal.Instant | Temporal.ZonedDateTime): Vitest

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vi.useFakeTimers
vi.useRealTimers
vi.advanceTimersByTime
vi.runAllTimers
Temporal.Now

Source: Vi | Vitest. Checked 2026-11-03.