需要结合key来使用。 v-for中的key是什么作用? key属性主要用在Vue的虚拟DOM算法,在新旧nodes对比时辨识VNodes。 如果不使用key,Vue会使用一种最大限度减少动态元素并且尽可能的尝试就地修改/复用相同类型元素的算法。 而使用key时,它会基于key的变化重新排列元素顺序,并且会移除/销毁key不存在的元素。 VNode是什么?
title: "春天", content: "我把裤衩一脱,春姑娘就来了"}, { id: 2, title: "夏天", content: "我把短裤一穿,夏姑娘就来了" } ]) </script> <template> <HelloWorld v-for="item in fatherItems" :key="item.id" :title="item
对象v-for = "(item,key,index) in obj " item是obj的属性值 json类型数据 v-for = “(item,index) in json” 嵌套类型数据 <ul> <li v-for = "item in lists"> <p>id: {{item.id}}</p> <ul> <li v-for = "task in item.task"> <p>task : {{ task}}</p> </li> </ul> <...
Previously, TypeScript would not consider any type guards onobj[key], and would have no idea thatobj[key]was really astring. Instead, it would think thatobj[key]was still astring | numberand accessingtoUpperCase()would trigger an error. TypeScript 4.7 now knows thatobj[key]is a string. Th...
If your package has typings specified using the types or typings key in its package.json, the npm registry will display that the package has available bindings like so: If you still can't find the typings, just look for any ".d.ts" files in the package and manually include them with ...
...<template><divclass="group-wrapper"><h3>{{groupLabel[props.status]}}</h3><ul><li v-for="todo in todoList":key="todo.id">{{todo.title}}<div><spanclass="todo-description">{{todo.description}}</span></div></li></ul></div></template><style lang="less"scoped>.group-wrappe...
label }}</div> <Menu @select="select" v-for="item in menu.children" :key="item.id" :menu="item" /> </template> <script lang="ts"> import { defineComponent } from "vue"; export default defineComponent({ name: "Menu", props: { menu: { type: Object, }, }, }); </script>...
K(Key):表示对象中的键类型 V(Value):表示对象中的值类型 E(Element):表示元素类型 12.4 泛型工具类型 为了方便开发者 TypeScript 内置了一些常用的工具类型,比如 Partial、Required、Readonly、Record 和 ReturnType 等。出于篇幅考虑,这里我们只简单介绍 Partial 工具类型。不过在具体介绍之前,我们得先介绍一些相关...
typeOmit<T,Kextendskeyofany>=Pick<T,Exclude<keyofT,K>>; Instead of making everyone define their own version ofOmit, TypeScript 3.5 will include its own inlib.d.tswhich can be used anywhere. The compiler itself will use thisOmittype to express types created through object rest destructuring...
字典(Map)与散列表(HashMap)是一种采用[键(key),值(value)]对的形式来存储数据的数据结构。 本文将详细讲解字典与散列表的实现思路并使用TypeScript将其实现,欢迎各位感兴趣的前端开发者阅读本文。 实现思路 字典与散列表存储数据的方式是键值对的形式来存储,因此我们可以使用JavaScript中的对象来实现。