Asymmetric matcher for property _not_ exists (opposite of anything)

[zirkelc]

Hey,

is there a way check if an object does not have a certain property? Basically, the opposite of expect.anything():

import { expect, test } from 'vitest'

test('object has "apples" key', () => {
  expect({ apples: 22 }).toEqual({ apples: expect.anything() }) // expect apples to exist
})

test('object has not "apples" key', () => {
  expect({ bananas: 22 }).toEqual({ apples: expect.nothing() }) // expect apples to NOT exist
})

I know you could use expect({ bananas: 22 }).not.toHaveProperty('apples'), but this doesn't really work when combined with expect.arrayContaining() and expect.objectContaining().

I think an asymmetric matcher like expect.nothing() that does a simple !('key' in obj) check would be really helpful.