[vue3]vue3+typescript上手案例：实现todoList

前言

todoList是常见的手撸代码题了。通过vue3的composition api实现todoList，掌握setup、ref、reactive、watch、toRefs、toRef等钩子函数，快速上手vue3+ts技术栈。建议有vue2基础的边看官方文档边做，以便快速熟悉相关hook，最后的实现效果图如下：

下面直接上代码。

Index页面

App.vue

<template>
  <div class="todo-container">
    <h1>TodoListh1>
    <div class="todo-wrap">
      <Header :addTodo="addTodo" />
      <List :todos="todos" :deleteTodo="deleteTodo" :updateTodo="updateTodo" />
      <Footer
        :todos="todos"
        :checkAll="checkAll"
        :clearAllCompletedTodos="clearAllCompletedTodos"
      />
    div>
  div>
template>
<script lang="ts">
import { defineComponent, onMounted, reactive, toRefs, watch } from "vue"
// 引入直接的子级组件
import Header from "@/components/todoList/Header.vue"
import List from "@/components/todoList/List.vue"
import Footer from "@/components/todoList/Footer.vue"

// 引入接口
import { Todo } from "@/types/todo"

// 数据持久化
import { saveTodos, readTodos } from "@/utils/localStorageUtils"

export default defineComponent({
  name: "App",
  // 注册组件
  components: {
    Header,
    List,
    Footer,
  },
  // 数据应该用数组来存储,数组中的每个数据都是一个对象,对象中应该有三个属性(id,title,isCompleted)
  // 把数组暂且定义在App.vue父级组件

  setup() {
    // 定义一个数组数据
    // const state = reactive<{ todos: Todo[] }>({
    //   todos: [
    //     { id: 1, title: "奔驰", isCompleted: false },
    //     { id: 2, title: "宝马", isCompleted: true },
    //     { id: 3, title: "奥迪", isCompleted: false },
    //   ],
    // })

    console.log("Demo11 setup")
    // console.log(state)

    const state = reactive<{ todos: Todo[] }>({
      todos: [],
    })
    // 界面加载完毕后过了一会再读取数据
    onMounted(() => {
      setTimeout(() => {
        state.todos = readTodos()
      }, 1000)
    })

    // 添加数据的方法
    const addTodo = (todo: Todo) => {
      state.todos.unshift(todo)
    }
    // 删除数据的方法
    const deleteTodo = (index: number) => {
      state.todos.splice(index, 1)
    }
    // 修改todo的isCompleted属性的状态
    const updateTodo = (todo: Todo, isCompleted: boolean) => {
      todo.isCompleted = isCompleted
    }

    // 全选或者是全不选的方法
    const checkAll = (isCompleted: boolean) => {
      state.todos.forEach(todo => {
        todo.isCompleted = isCompleted
      })
    }

    // 清理所有选中的数据
    const clearAllCompletedTodos = () => {
      state.todos = state.todos.filter(todo => !todo.isCompleted)
    }

    // 监视操作:如果todos数组的数据变化了,直接存储到浏览器的缓存中 有多种写法
    // watch(()=>state.todos,(value)=>{
    //   // 保存到浏览器的缓存中
    //   localStorage.setItem('todos_key',JSON.stringify(value))
    // },{deep:true})

    // watch(
    //   () => state.todos,
    //   (value) => {
    //     // 保存到浏览器的缓存中
    //     saveTodos(value)
    //   },
    //   { deep: true }
    // )

    watch(() => state.todos, saveTodos, { deep: true })

    return {
      ...toRefs(state),
      addTodo,
      deleteTodo,
      updateTodo,
      checkAll,
      clearAllCompletedTodos,
    }
  },
})
script>
<style scoped>
/*app*/
.todo-container {
  width: 600px;
  margin: 0 auto;
}
.todo-container .todo-wrap {
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 5px;
}
style>

工具函数

主要用于数据持久化到localStorage中，这里也可存到cookies中。

utils/localStorageUtils.ts

import { Todo } from '@/types/todo'
// 保存数据到浏览器的缓存中
export function saveTodos(todos: Todo[]) {
  localStorage.setItem('todos_key', JSON.stringify(todos))
}
// 从浏览器的缓存中读取数据
export function readTodos(): Todo[] {
  return JSON.parse(localStorage.getItem('todos_key') || '[]')
}

ts类型定义

src/types/todo.ts

// 定义一个接口,约束state的数据类型
export interface Todo {
    id: number,
    title: string,
    isCompleted: boolean
}

Item组件

components/todoList/Item.vue

<template>
  <li
    @mouseenter="mouseHandler(true)"
    @mouseleave="mouseHandler(false)"
    :style="{ backgroundColor: bgColor, color: myColor }"
  >
    <label>
      <input type="checkbox" v-model="isComptete" />
      <span>{{ todo.title }}span>
    label>
    <button class="btn btn-danger" v-show="isShow" @click="delTodo">
      删除
    button>
  li>
template>
<script lang="ts">
import { defineComponent, ref, computed } from "vue"
// 引入接口
import { Todo } from "@/types/todo"
export default defineComponent({
  name: "Item",
  props: {
    todo: {
      type: Object as () => Todo, // 函数返回的是Todo类型
      required: true,
    },
    deleteTodo: {
      type: Function,
      required: true,
    },
    index: {
      type: Number,
      required: true,
    },
    updateTodo: {
      type: Function,
      required: true,
    },
  },

  setup(props: any) {
    const todo: Todo = props.todo

    // 背景色
    const bgColor = ref("white")
    // 前景色
    const myColor = ref("black")
    // 设置按钮默认不显示
    const isShow = ref(false)
    // 鼠标进入和离开事件的回调函数
    const mouseHandler = (flag: boolean) => {
      if (flag) {
        // 鼠标进入
        bgColor.value = "pink"
        myColor.value = "green"
        isShow.value = true
      } else {
        // 鼠标离开
        bgColor.value = "white"
        myColor.value = "black"
        isShow.value = false
      }
    }
    // 删除数据的方法
    const delTodo = () => {
      // 提示
      if (window.confirm("确定要删除吗?")) {
        props.deleteTodo(props.index)
      }
    }
    // 计算属性的方式---来让当前的复选框选中/不选中
    const isComptete = computed({
      get() {
        return todo.isCompleted
      },
      set(val) {
        props.updateTodo(todo, val)
      },
    })
    return {
      mouseHandler,
      bgColor,
      myColor,
      isShow,
      delTodo,
      isComptete,
    }
  },
})
script>
<style scoped>
/*item*/
li {
  list-style: none;
  height: 36px;
  line-height: 36px;
  padding: 0 5px;
  border-bottom: 1px solid #ddd;
}

li label {
  float: left;
  cursor: pointer;
}

li label li input {
  vertical-align: middle;
  margin-right: 6px;
  position: relative;
  top: -1px;
}

li button {
  float: right;
  /* display: none; */
  margin-top: 3px;
}

li:before {
  content: initial;
}

li:last-child {
  border-bottom: none;
}
style>

List组件

components/todoList/List.vue

<template>
  <ul class="todo-main">
    <Item
      v-for="(todo, index) in todos"
      :key="todo.id"
      :todo="todo"
      :deleteTodo="deleteTodo"
      :updateTodo="updateTodo"
      :index="index"
    />
  ul>
template>
<script lang="ts">
import { defineComponent } from "vue"
// 引入子级组件
import Item from "./Item.vue"
export default defineComponent({
  name: "List",
  components: {
    Item,
  },
  props: ["todos", "deleteTodo", "updateTodo"],

  setup(props: any, context: any) {
    console.log(props)
    console.log(context)
  },
})
script>
<style scoped>
/*main*/
.todo-main {
  margin-left: 0px;
  border: 1px solid #ddd;
  border-radius: 2px;
  padding: 0px;
}

.todo-empty {
  height: 40px;
  line-height: 40px;
  border: 1px solid #ddd;
  border-radius: 2px;
  padding-left: 5px;
  margin-top: 10px;
}
style>

Header组件

components/todoList/Header.vue

<template>
  <div class="todo-header">
    <input
      type="text"
      placeholder="请输入你的任务名称，按回车键确认"
      v-model="title"
      @keyup.enter="add"
    />
  div>
template>
<script lang="ts">
import { defineComponent, ref } from "vue"
import { Todo } from "@/types/todo"
// 定义接口,约束对象的类型

export default defineComponent({
  name: "Header",
  props: {
    addTodo: {
      type: Function,
      required: true, // 必须
    },
  },

  setup(props: any) {
    // 定义一个ref类型的数据
    const title = ref("")

    // 回车的事件的回调函数,用来添加数据
    const add = () => {
      // 获取文本框中输入的数据,判断不为空
      const text = title.value
      if (!text.trim()) return
      // 此时有数据,创建一个todo对象
      const todo = {
        id: Date.now(),
        title: text,
        isCompleted: false,
      }

      // 调用方法addTodo的方法
      props.addTodo(todo)
      console.log("添加todo", todo)

      // 清空文本框
      title.value = ""
    }
    return {
      title,
      add,
    }
  },
})
script>
<style scoped>
/*header*/
.todo-header input {
  width: 560px;
  height: 28px;
  font-size: 14px;
  border: 1px solid #ccc;
  border-radius: 4px;
  padding: 4px 7px;
}

.todo-header input:focus {
  outline: none;
  border-color: rgba(82, 168, 236, 0.8);
  box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075),
    0 0 8px rgba(82, 168, 236, 0.6);
}
style>

Footer组件

components/todoList/Footer.vue

<template>
  <div class="todo-footer">
    <label>
      <input type="checkbox" v-model="isCheckAll" />
    label>
    <span>
      <span>已完成{{ count }}span> / 全部{{ todos.length }}
    span>
    <button class="btn btn-danger" @click="clearAllCompletedTodos">
      清除已完成任务
    button>
  div>
template>
<script lang="ts">
import { defineComponent, computed } from "vue"
import { Todo } from "@/types/todo"
export default defineComponent({
  name: "Footer",
  props: {
    todos: {
      type: Array as () => Todo[],
      required: true,
      default: [],
    },
    checkAll: {
      type: Function,
      required: true,
    },
    clearAllCompletedTodos: {
      type: Function,
      required: true,
    },
  },
  setup(props: any) {
    console.log("Footer setup")
    console.log(props.todos)

    // 已完成的计算属性操作
    const count = computed(() => {
      console.log("Footer computed todos")
      console.log(props.todos)
      return props.todos.reduce(
        (pre, todo, index) => pre + (todo.isCompleted ? 1 : 0),
        0
      )
    })

    // 全选/全不选的计算属性操作
    const isCheckAll = computed({
      get() {
        return count.value > 0 && props.todos.length === count.value
      },
      set(val) {
        props.checkAll(val)
      },
    })
    return {
      count,
      isCheckAll,
    }
  },
})
script>
<style scoped>
/*footer*/
.todo-footer {
  height: 40px;
  line-height: 40px;
  padding-left: 6px;
  margin-top: 5px;
}

.todo-footer label {
  display: inline-block;
  margin-right: 20px;
  cursor: pointer;
}

.todo-footer label input {
  position: relative;
  top: -1px;
  vertical-align: middle;
  margin-right: 5px;
}

.todo-footer button {
  float: right;
  margin-top: 5px;
}
style>