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一周一个小demo — vue.js实现备忘录功能

2024-10-20 18:43:02   209人阅读

这个vue实现备忘录的功能demo是K在github上找到的，K觉得这是一个用来对vue.js入门的一个非常简单的demo，所以拿在这里共享一下。

（尊重他人劳动成果，从小事做起~  demo原github地址：https://github.com/vuejs/vue）

一、实现效果

 技术分享

 

二、代码展示

<!DOCTYPE html>
<html>

    <head>
        <meta charset="UTF-8">
        <title>备忘录</title>
        <link rel="stylesheet" type="text/css" href="css/index.css" />
        <style>[v-cloak] { display: none; }</style>
    </head>

    <body>
    <section class="todoapp">
      <header class="header">
        <h1>todos</h1>
        <input class="new-todo"
          autofocus autocomplete="off"
          placeholder="What needs to be done?"
          v-model="newTodo"
          @keyup.enter="addTodo">
      </header>
      <section class="main" v-show="todos.length" v-cloak>
        <input class="toggle-all" type="checkbox" v-model="allDone">
        <ul class="todo-list">
          <li v-for="todo in filteredTodos"
            class="todo"
            :key="todo.id"
            :class="{ completed: todo.completed, editing: todo == editedTodo }">
            <div class="view">
              <input class="toggle" type="checkbox" v-model="todo.completed">
              <label @dblclick="editTodo(todo)">{{ todo.title }}</label>
              <button class="destroy" @click="removeTodo(todo)"></button>
            </div>
            <input class="edit" type="text"
              v-model="todo.title"
              v-todo-focus="todo == editedTodo"
              @blur="doneEdit(todo)"
              @keyup.enter="doneEdit(todo)"
              @keyup.esc="cancelEdit(todo)">
          </li>
        </ul>
      </section>
      <footer class="footer" v-show="todos.length" v-cloak>
        <span class="todo-count">
          <strong>{{ todos.length }}</strong> {{ remaining | pluralize }} left
        </span>
        <ul class="filters">
          <li><a href="#/all" :class="{ selected: visibility == ‘all‘ }">All</a></li>
          <li><a href="#/active" :class="{ selected: visibility == ‘active‘ }">Active</a></li>
          <li><a href="#/completed" :class="{ selected: visibility == ‘completed‘ }">Completed</a></li>
        </ul>
        <button class="clear-completed" @click="removeCompleted" v-show="todos.length > remaining">
          Clear completed
        </button>
      </footer>
    </section>
        <footer class="info">
            <p>双击编辑一条备忘录</p>
        </footer>

    </body>

    <script language="JavaScript" src="js/director.js"></script>
    <script language="JavaScript" src="js/vue.js"></script>
    <script language="JavaScript" src="js/index_vue.js"></script>

</html>
// 本地缓存设置
// 防止页面关闭后，数据全部丢失的问题
var STORAGE_KEY = ‘todos-vuejs-2.0‘
var todoStorage = {
    
    // 获取本地存储中的内容
    fetch:function(){
        //  JSON.parse()解析一个json字符串
        //    localStorage.getItem 从本地存储中获取STORAGE_KEY字段的值
        var todos = JSON.parse(localStorage.getItem(STORAGE_KEY)||‘[]‘);
        //    foreach遍历todos，两个参数分别为遍历出的每一个子单元及对应的索引
        todos.forEach(function(todo,index){
            todo.id = index;
        })
        todoStorage.uid = todos.length;
        return todos;
    },
    
    // 保存时将内容写进本地存储
    save:function(todos){
        // localStorage.setItem 将todos转化成字符串存入本地存储，键名为STORAGE_KEY
        localStorage.setItem(STORAGE_KEY,JSON.stringify(todos))
    }
    
}

// 可视化状态过滤设置
//    包括全选（all）、选择未完成（active）、选择已完成（completed）
var filters = {
    all:function(todos){
        return todos;
    },
    
    //    filter() 方法创建一个新的数组，新数组中的元素是通过检查指定数组中符合条件的所有元素。
    active:function(todos){
        return todos.filter(function(todo){
            return !todo.completed;
        })
    },
    
    completed:function(todos){
        return todos.filter(function(todo){
            return todo.completed;
        })
    }
}


// vue实例化
var app = new Vue({
    
    //    data 参数设置
    data:{
        todos:todoStorage.fetch(),
        newTodo:‘‘,
        editedTodo:null,
        visibility:‘all‘
    },
    
    //    watch 监视todos在本地储存中的变化
    watch:{
        todos:{
            handler:function(todos){
                todoStorage.save(todos)
            },
            deep:true
        }
    },
    
    //    computed 检测数据发生变动时执行函数
    computed:{
        
        filteredTodos:function(){
            return filters[this.visibility](this.todos)
        },
        
        remaining:function(){
            return filters.active(this.todos).length
        },
        
        allDone:{
            get:function(){
                return this.remaining === 0
            },
            
            set:function(value){
                this.todos.forEach(function(todo){
                    todo.completed = value
                })
            }
            
        }
    },
    
    //    methods 方法设置
    methods:{
        addTodo:function(){
            var value = http://www.mamicode.com/this.newTodo && this.newTodo.trim()
            if(!value){
                return;
            }
            this.todos.push({
                id:todoStorage.uid++,
                title:value,
                completed:false
            })
            this.newTodo = ‘‘
        },
        
        removeTodo:function(todo){
            this.todos.splice(this.todos.indexOf(todo),1)
        },
        
        editTodo:function(todo){
            this.beforeEditCache = todo.title;
            this.editedTodo = todo
        },
        
        doneEdit:function(todo){
            if(!this.editedTodo){
                return;
            };
            this.editedTodo = null;
            todo.title = todo.title.trim()
            if(!todo.title){
                this.removeTodo(todo)
            }
        },
        
        cancelEdit:function(todo){
            this.editedTodo = null;
            todo.title = this.beforeEditCache
        },
        
        removeCompleted:function(){
            this.todos = filters.active(this.todos)
        }
    },
    
    directives:{
        ‘todo-focus‘:function(el,binding){
            if(binding.value){
                el.focus()
            }
        }
    }
})


// hashchange URL的片段标识符更改触发
function onHashChange(){
    var visbility = window.location.hash.replace(/#\/?/, ‘‘);
    if(filters[visbility]){
        app.visibility = visbility
    }else{
        window.location.hash = ‘‘;
        app.visbility = ‘all‘
    }
}

window.addEventListener(‘hashchange‘,onHashChange)
onHashChange()

// mount 手动挂载
app.$mount(‘.todoapp‘)

 

一周一个小demo — vue.js实现备忘录功能


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