Function isMockFunction

packages/spy/src/index.ts:17–21

(fn: any)

} from './types'

export function isMockFunction(fn: any): fn is Mock {
  return (
    typeof fn === 'function' && '_isMockFunction' in fn && fn._isMockFunction === true
  )
}

const MOCK_RESTORE = new Set<() => void>()
// Jest keeps the state in a separate WeakMap which is good for memory,