Question

你好，我在应用程序中多次使用选择器。我可以编写一次代码然后导入选择器吗？我曾想编写一个自定义钩子，但我认为这是没有必要的。这是我的选择器：

    ...

    # EVENTS
    for event in pygame.event.get():
        # Quitting
        if event.type == pygame.QUIT:
            sys.exit()

    pressed = pygame.key.get_pressed()
    jet_xincrement = 0
    if pressed[pygame.K_RIGHT]: jet_xincrement += 3
    if pressed[pygame.K_LEFT]: jet_xincrement -= 3

    boundaries()
    move_jet(jet_xincrement)

    pygame.display.flip()

如果我有这样的东西，那就太好了

const county = useSelector((state)=>{
    const id = state.user.id
    const name = state.user.name
    return state.users.filter((user) => user.name === name)[0].county
})

Answer 1

您可以在useSelector中传递箭头功能

export const countySelector = state => {
    const id = state.user.id;
    const name = state.user.name;
    return state.users.find(user => user.name === name).county;
};

// Usage
import { countySelector } from 'selectors';
const county = useSelector(countySelector);

或创建自定义钩子

const useCounty = () => {
    return useSelector(state => {
        const id = state.user.id;
        const name = state.user.name;
        return state.users.find(user => user.name === name).county;
    });
};

export default useCounty;

// Usage
import useCounty from 'useCounty';
const county = useCounty();

Answer 2

标准redux template随同redux工具包一起提供，reselect也随同。 Here是如何创建可组合的备忘选择器的一些示例。

在应用中多次使用useSelector反应redux

2 个答案: