Javascript 带Jest的单元测试requestAnimationFrame

当我调整单元测试时，我遇到了一个问题，这让我有一段时间处于混乱状态。我在开玩笑，没有反应，没有酶，也没有其他兄弟

我在一个函数中停止了，在返回之前，我有两个条件，不知道如何调用和测试

rAF

requestAnimationFrame

的回调。我的登录功能如下所示：

const myFn = (dispatch, options) => {
    const { state } = options;
    const { isScrolling } = state;
    const scrollOptions = { behavior: 'smooth', block: 'end' };
    const wrapper = document.getElementById(options.wrapperId);
    const target = document.getElementById(options.elementId);

    wrapper && wrapper.addEventListener('scroll', () => {
        wrapper.scrollHeight - (wrapper.offsetHeight + wrapper.scrollTop + OFFSET) <= 20
            ?
            dispatch(scrollingOn(state))
            :
            dispatch(scrollingOff(state));
    });

    return setTimeout(() => {
        if (target && isScrolling) {
            target.scrollIntoView(scrollOptions);
        }
    }, 500);
};

export const ScrollIntoView = (state, elementId, wrapperId, interval) => [myFn, { state, elementId, wrapperId}];

我的DOM模拟看起来像：

    scrollIntoView: jest.fn(),
    addEventListener: jest.fn(listener => listener),
    scrollHeight: 123,
    clientHeight: 122,
    scrollTop: 123,
    offsetHeight: 200,
    focus: jest.fn(),
    scroll: jest.fn(),
    id: 'mockedElement',
    style: {
        overflowY: 'inherit',
        height: 1
    }
};

export const domMock = () => {
    return {
        getElementById: () => htmlElement,
        addEventListener: jest.fn(listener => listener)
    };
};

And the place where I'm stacked is line 59 where I'm trying test rAF. 
[![enter image description here][1]][1]


  [1]: https://i.stack.imgur.com/LgB6Z.png

I would be thankful for if someone to share experience in testing rAF and how can test the callback.

---

我看到这里的问题是在第一眼看到的时候就调度了scroll事件。

    scrollIntoView: jest.fn(),
    addEventListener: jest.fn(listener => listener),
    scrollHeight: 123,
    clientHeight: 122,
    scrollTop: 123,
    offsetHeight: 200,
    focus: jest.fn(),
    scroll: jest.fn(),
    id: 'mockedElement',
    style: {
        overflowY: 'inherit',
        height: 1
    }
};

export const domMock = () => {
    return {
        getElementById: () => htmlElement,
        addEventListener: jest.fn(listener => listener)
    };
};

And the place where I'm stacked is line 59 where I'm trying test rAF. 
[![enter image description here][1]][1]


  [1]: https://i.stack.imgur.com/LgB6Z.png

I would be thankful for if someone to share experience in testing rAF and how can test the callback.