vi.mock with a Factory in Vitest
From the Vitest cheat sheet · Module Mocking · verified Nov 2026
vi.mock with a Factory
Replace a module, or only some of its exports, with a factory
typescript
import { fetchUser } from './api'
vi.mock('./api', () => ({
fetchUser: vi.fn().mockResolvedValue({ id: 1, name: 'Ada' }),
}))
test('uses the mock', async () => {
expect(await fetchUser(1)).toEqual({ id: 1, name: 'Ada' })
})📌 vi.mock is hoisted above imports and must sit at the top level
⚠️ v5 throws if vi.mock is called inside describe, test or a function
💡 vi.mock(import('./x'), ...) gives you a typed importOriginal
🔍 Return a default key for default exports, unlike Jest factories
vi.mockmodule-mockingimportOriginal
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