1、功能描述

1、可以添加当天的任务到任务清单
2、可以勾选已经完成的项目
3、统计任务数量以及完成数量
4、删除已完成的任务
5、可以查看当天的任务清单（关闭网页重新打开同样可以看到）

2、效果演示

视频链接：https://live.csdn.net/v/230827

3、在实战三代码上修改（核心部分代码、将数据保存到浏览器）

<template>
  <div id="root">
    <div class="todo-container">
      <div class="todo-wrap">
        <TheHeader :addTodo="addTodo" />
        <TheList
          :todos="todos"
          :checkTodo="checkTodo"
          :deleteTodo="deleteTodo"
        />
        <TheFooter
          :todos="todos"
          :checkAllTodo="checkAllTodo"
          :clearAllTodo="clearAllTodo"
        />
      </div>
    </div>
  </div>
</template>

<script>
import TheHeader from "./components/TheHeader";
import TheList from "./components/TheList";
import TheFooter from "./components/TheFooter.vue";

export default {
  name: "App",
  components: { TheHeader, TheList, TheFooter },
  data() {
    return {
      //由于todos是MyHeader组件和MyFooter组件都在使用，所以放在App中（状态提升）
      todos: JSON.parse(localStorage.getItem("todos")) || [],
      // todos: [
      //   { id: "001", title: "吃饭", done: true },
      //   { id: "002", title: "睡觉", done: false },
      //   { id: "003", title: "打豆豆", done: true },
      // ],
    };
  },
  methods: {
    //添加一个todo
    addTodo(todoObj) {
      this.todos.unshift(todoObj);
    },
    //勾选or取消勾选一个todo
    checkTodo(id) {
      this.todos.forEach((todo) => {
        if (todo.id === id) todo.done = !todo.done;
      });
    },

    //删除一个todo
    deleteTodo(id) {
      this.todos = this.todos.filter((todo) => todo.id !== id);
    },
    //全选or取消全选
    checkAllTodo(done) {
      this.todos.forEach((todo) => {
        todo.done = done;
      });
    },
    //清除所有已经完成的todo
    clearAllTodo() {
      this.todos = this.todos.filter((todo) => {
        return !todo.done;
      });
    },
  },
  watch: {
    todos: {
      deep: true,
      handler(value) {
        localStorage.setItem("todos", JSON.stringify(value));
      },
    },
  },
};
</script>

<style>
/*base*/
body {
  background: #fff;
}
.btn {
  display: inline-block;
  padding: 4px 12px;
  margin-bottom: 0;
  font-size: 14px;
  line-height: 20px;
  text-align: center;
  vertical-align: middle;
  cursor: pointer;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.2),
    0 1px 2px rgba(0, 0, 0, 0.05);
  border-radius: 4px;
}
.btn-danger {
  color: #fff;
  background-color: #da4f49;
  border: 1px solid #bd362f;
}
.btn-danger:hover {
  color: #fff;
  background-color: #bd362f;
}
.btn:focus {
  outline: none;
}
.todo-container {
  width: 600px;
  margin: 0 auto;
}
.todo-container .todo-wrap {
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 5px;
}
</style>