javascript - 开玩笑的错误” TypeError:无法读取未定义的属性'preventDefault'

我有如下功能，当我要测试该功能时，出现上述错误。
功能

toggleRecovery = e => {
    e.preventDefault()
    this.setState(
      {
        recovery: !this.state.recovery
      },
      () => {
        this.props.reset()
      }
    )
  }

测试

test('if the recovery state is true should set the state to the false', () => {
      wrapper.setState({ recovery: true })
      //Check if the state is true initially
      expect(wrapper.state().recovery).toBeTruthy()
      //Calling the toggleRecovery()
      wrapper.instance().toggleRecovery()
      expect(wrapper.state().recovery).toBeFalsy()
      expect(props.reset).toHaveBeenCalled()
    })

错误

TypeError: Cannot read property 'preventDefault' of undefined

我如何克服此错误，是什么原因导致上述错误

最佳答案

在实例上调用toggleRecovery时，您可以像下面那样传递preventDefault模拟

test('if the recovery state is true should set the state to the false', () => {
      wrapper.setState({ recovery: true })
      //Check if the state is true initially
      expect(wrapper.state().recovery).toBeTruthy()
      //Calling the toggleRecovery()
      wrapper.instance().toggleRecovery({
          preventDefault: () => {
      })
      expect(wrapper.state().recovery).toBeFalsy()
      expect(props.reset).toHaveBeenCalled()
    })