Vue3开发踩坑

前端开发博客 2020-11-08 19:27:13
开发 vue 技术开发 SegmentFault vue3


作者:vita2333
链接:https://juejin.im/post/689231...

期待了很久的vue3,一发布就上手体验了一把,这里记录几个自己碰到的网上不常见的小坑~

自定义全局参数

定义:

// main.js
const app = createApp(App)
app.config.globalProperties.$test = 'test'

除了setup()需要先获得实例,其他地方可以直接通过$test使用:

<tempalte>
<div>{{ $test }}</div>
</tempalte>
<script>
import { getCurrentInstance } from 'vue'
export default {
setup() {
const test = getCurrentInstance()?.appContext.config.globalProperties.$test
console.log('test===')
console.log(test)
},
}
</script>

Vite通过alias别名引用

webpack中,配置src的别名为@,可以这么写:

// 引用src/views/PageOne.vue
import PageOne from '@/views/PageOne.vue'
复制代码

如果使用Vite,则需要做以下修改:

// vite.config.js
module.exports={
alias: {
'/@/': path.resolve(__dirname, './src'),
},
}
// tsconfig.json
{
"compilerOptions": {
"paths": {
"@/*": ["src/*"],
"/@/views/*": ["src/views/*"]
}
}
}
import PageOne from '/@/views/PageOne.vue'

更加规范的props和emits

vue3中,父子组件传值的propsemits写法更加规范(命名更统一),体现在:

  1. v-model的变化
<template>
<child-component v-model:value="myValue"></child-component>
</template>

v-model:value等同于props:'value'emits('update:value')

  1. 需要指定emits

为了便于管理,建议在emits中定义所有用到的emit

 export default {
emits: ['update:value', 'otherEmit'],
setup(props, { emit }) {
emit('update:value')
emit('otherEmit')
},
}

跟踪attrs和slots

本来以为可以通过watch()函数直接watch(()=>attrs.xxx),结果是不行。这里官网有些,一开始自己没注意:

attrs 和 slots 是有状态的对象,它们总是会随组件本身的更新而更新。这意味着你应该避免对它们进行解构,并始终以 attrs.x 或 slots.x 的方式引用 property。请注意,与 props 不同,attrs 和 slots 是非响应式的。如果你打算根据 attrs 或 slots 更改应用副作用,那么应该在 onUpdated 生命周期钩子中执行此操作。

所以要响应式处理attrsslots,就需要:

import { onUpdated, reactive, watch, watchEffect } from 'vue'
export default {
setup(props, { attrs }) {
function _handleAttrsChange() {
console.log('attrs===')
console.log(attrs)
}
onUpdated(() => {
_handleAttrsChange()
})
// props和data可以正常使用watch函数
watchEffect(() => {
console.log('propsXxx===')
console.log(props.xxx)
})
const state = reactive({ count: 0 })
watch(() => state.count, (now, old) => {
//
})
},
}

VueRouter不能直接使用含有props的组件

我有一个地址列表AddressList,需要通过props接收父组件参数:

// router.js
export default {
name: 'AddressList',
props: {
propName: String,
},
}

通过组件调用,没有问题。但是配置为vue-router项时会报错:

export default {
routes: [
{
path: 'address_list',
component: () => import( 'AddressList.vue'),
},
],
}
TypeError: Cannot add property __props, object is not extensible

既然不能直接将组件作为route使用,那么就在其他页面中调用就好了

// router.js
export default {
routes: [
{
path: 'address_list',
component: () => import( 'Page.vue'),
meta: { component: 'AddressList' },
},
],
}
<!--Page.vue-->
<template>
<component :is="component" />
</template>
<script lang="ts">
import AddressList from '/@/views/AddressList.vue'
import { defineComponent } from 'vue'
export default defineComponent({
name: 'Page',
components: { AddressList },
computed: {
component () {
return this.$route.meta.component
},
},
})
</script>

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