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Vitest · Type Alias

MockInstance

Vitest MockInstance objects let tests inspect calls and control mock functions, spies, and mocked classes. Use vi.fn for a new mock and vi.spyOn for an existing object method.

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Syntax

vi.fn(implementation?)
vi.spyOn(object, method)
vi.mock(path, factory?)

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  • vi.fn
  • vi.spyOn
  • vi.mock
  • vi.hoisted
  • mock.calls
  • mock.instances
  • toHaveBeenCalled

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