vuex中key => [key, computed(() => store.state[key])]
时间: 2024-01-13 20:02:44 浏览: 17
这是一个计算属性数组,其中第一个元素是 Vuex store 中的一个 state 属性的 key,第二个元素是一个计算属性,它会返回对应 key 的 state 值。这个数组可以用在 Vue 组件中,可以通过解构赋值来获取计算属性返回的值。
例如:
```
<template>
<div>
<p>{{ count }}</p>
<button @click="increment">+</button>
</div>
</template>
<script>
import { mapState, mapActions } from 'vuex'
export default {
computed: {
...mapState([
'count',
['doubleCount', computed(() => this.$store.state.count * 2)]
])
},
methods: {
...mapActions([
'increment'
])
}
}
</script>
```
在上面的例子中,`doubleCount` 是一个计算属性,它会返回 `count` 的两倍。我们可以在组件中通过 `this.doubleCount` 来获取这个值。
相关问题
优化此代码 const openKeys = ref<string[]>([]) const selectedKeys = ref<string[]>([]) const { currentMenu, currentMenuTree, currentMenuList } = storeToRefs( useLayoutStore(), ) const rootSubmenuKeys = currentMenuList.value.filter((v: any) => { if (v.type === 0) { return v.parentId } }) watch( () => currentMenu, () => { openKeys.value = [currentMenu.value?.parentId] selectedKeys.value = [currentMenu.value?.id] }, { immediate: true }, ) const router = useRouter() /** * 点击事件 * @param e 事件对象 */ const handleClick = (e: any) => { const item = currentMenuList.value.find((_) => _.id === e.key) if (item) { router.push(item.path) } } /** * SubMenu 展开/关闭的回调 * @param e 展开的openKeys */ const onOpenChange = (e: any) => { const latestOpenKey = e.find((key: any) => openKeys.value.indexOf(key) === -1) if (rootSubmenuKeys.indexOf(latestOpenKey) === -1) { openKeys.value = e } else { openKeys.value = latestOpenKey ? [latestOpenKey] : [] } }
There are a few optimizations that could be made to this code:
1. Instead of using `ref` for `openKeys` and `selectedKeys`, you can use `reactive` to make the code more concise:
```
const state = reactive({
openKeys: [],
selectedKeys: [],
})
```
2. Instead of using `storeToRefs` to convert the store state to refs, you can use the `toRefs` function, which is shorter and more concise:
```
const { currentMenu, currentMenuTree, currentMenuList } = toRefs(useLayoutStore())
```
3. Instead of using `watch` to watch the `currentMenu` state changes, you can use a computed property to update the `openKeys` and `selectedKeys` arrays:
```
const selectedMenu = computed(() => {
const item = currentMenuList.value.find((_) => _.id === currentMenu.value?.id)
return [item?.id] || []
})
const parentMenu = computed(() => {
const item = currentMenuList.value.find((_) => _.id === currentMenu.value?.parentId)
return [item?.id] || []
})
watch([selectedMenu, parentMenu], ([selected, parent]) => {
state.selectedKeys = selected
state.openKeys = parent
})
```
4. Instead of using `router.push` in the `handleClick` function, you can use the `router.push` method directly in the template:
```
<Menu.Item :key="item.id" :to="item.path">{{ item.name }}</Menu.Item>
```
5. Finally, instead of using `rootSubmenuKeys` to filter the list of menu items, you can use a computed property to filter the list of menu items based on their type:
```
const subMenuItems = computed(() => {
return currentMenuList.value.filter((v: any) => v.type === 0 && v.parentId)
})
```
By applying these optimizations, the code can be simplified and made more concise.
<div v-for="(item, index) in $store.state.category" :key="index"> <div class="bg">{{ item.category | showFirst }}</div> <div class="name">{{ item.category }}</div> </div>,对div添加背景颜色。
要为上述代码中的每个 `div` 元素添加背景颜色,你可以在 `item` 对象中添加一个 `color` 属性,并将其与背景颜色关联起来。以下是一个示例:
```html
<template>
<div>
<div v-for="(item, index) in $store.state.category" :key="index" :style="{ backgroundColor: item.color }">
<div class="bg">{{ item.category | showFirst }}</div>
<div class="name">{{ item.category }}</div>
</div>
</div>
</template>
<script>
export default {
computed: {
$store() {
return this.$store;
}
},
filters: {
showFirst: function(value) {
return value.charAt(0);
}
},
mounted() {
this.$store.state.category.forEach((item) => {
item.color = getRandomColor();
});
}
};
function getRandomColor() {
const letters = '0123456789ABCDEF';
let color = '#';
for (let i = 0; i < 6; i++) {
color += letters[Math.floor(Math.random() * 16)];
}
return color;
}
</script>
```
在上面的示例中,我们使用 `v-for` 指令遍历 `$store.state.category` 数组,并为每个循环项 `item` 添加了一个 `color` 属性,该属性在 `mounted` 钩子函数中被赋予随机的背景颜色。
然后,我们使用 `:style` 指令将 `backgroundColor` 属性与 `item.color` 关联起来,从而为 `div` 元素添加背景颜色。
请注意,上述示例中的 `getRandomColor` 函数用于生成随机的背景颜色。你可以根据需要自定义生成颜色的逻辑。
最后,我们还添加了一个名为 `showFirst` 的过滤器,用于仅显示每个类别的第一个字符。你可以根据需要自定义过滤器的逻辑。