Componentized coding process--Todo-list case

1. Component coding process

1. Split static components:

        Components are split according to function points , and the naming should not conflict with html elements ;

2. Implement dynamic components:

Consider where the data is stored , whether the data is used by a component or some components;

(1): A component is in use:

        Just put it in the component itself ;

(2): Some components are in use:

on their common parent component ( state hoisting )

3. Realize interaction:

Start with binding events;

2. Matters needing attention:

1. The use of props:

(1) Parent component ==> child component communicates;

(2) Child component ==> parent component communicates (requires the parent component to pass a function to the child component );

2. The use of v-model:

(1) The value bound by v-model cannot be the value passed by props, because props cannot be modified ;

(2) If the value passed by props is an object type value, Vue will not report an error when modifying the properties in the object , but this is not recommended ;

Example code of todoList project:

app.vue

<template>
    <div id="root">
        <div class="todo-container">
            <div class="todo-wrap">
                <MyHeader :addTodo='addTodo'/>
                <MyList :todos="todos" :checkTodo="checkTodo" :deleteTodo='deleteTodo'/>
                <MyFooter :todos="todos" :checkAllTodo="checkAllTodo" :clearAllTodo="clearAllTodo"/>
            </div>
        </div>
</div>
</template>

<script>
    import MyHeader from './components/MyHeader.vue'
    import MyList from './components/MyList'
    import MyFooter from './components/MyFooter'
    

    export default {
        name:'App',
        components:{
            MyHeader,
            MyFooter,
            MyList
        },
        data(){
            return{
                todos:[
                    {id:'001',title:'学习',done:true},
                    {id:'002',title:'开车',done:false},
                    {id:'003',title:'打游戏',done:false}
                ]
            }
        },
        methods:{
            // 实现添加一个todoObj
            addTodo(todoObj){
                this.todos.unshift(todoObj)
            },
            // 更新被修改的todoObj的数据，取消 or 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)=>{
                    return todo.id != id
                })
            },
            // 全选 or 取消全选
            checkAllTodo(done){
                this.todos.forEach((todo)=>{
                    todo.done=done
                })
            },
            clearAllTodo(){
                this.todos = this.todos.filter((todo)=>{
                    return !todo.done
                })
            }
        }
    }
</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>

MyHeader.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" @keyup.enter="add"/>
    </div>
</template>

<script>
// 这里要加大括号{}
import {nanoid} from 'nanoid'
export default {
    name:'MyHeader',
    props:['addTodo'],
    methods:{
        add(e){
            // 将用户的输入包装为一个todo对象
            const todoObj = {id:nanoid(),title:e.target.value,done:false}
            this.addTodo(todoObj)
            e.target.value=''
        }
    },
    
    
}
</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>

MyList.vue

<template>
  <ul class="todo-main">
        <MyItem 
            v-for="todoObj in todos" 
            :key="todoObj.id" 
            :todo="todoObj" 
            :checkTodo="checkTodo"
            :deleteTodo="deleteTodo"
        />
    </ul>
</template>

<script>
import MyItem from './MyItem.vue';
export default {
    name:"MyList",
    components: { MyItem },
    props:['todos','checkTodo','deleteTodo']
    
}
</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>

MyItem.view

<template>
    <li>
        <label>
            <!-- 这里的@change也可以使用@click -->
            <!-- 这里其实也可以使用v-model="todo.done"实现，但是不建议，因为会引起props中todo的数据的改变，之所以不报错是因为改变的是隐藏在todo中的done，props识别不了 -->
            <input type="checkbox" :checked="todo.done" @change="changeTodoObj(todo.id)"/>
            <span>{
   
   {todo.title}}</span>
        </label>
        <button class="btn btn-danger" @click="HeaderDelete(todo.id)">删除</button>
    </li>
</template>

<script>
export default {
    // 这里其实
    props:['todo','checkTodo','deleteTodo'],
    methods:{
        // 勾选 or 取消勾选
        changeTodoObj(id){
            this.checkTodo(id)
        },
        // 删除
        HeaderDelete(id){    
            if(confirm('确定删除？')){
                this.deleteTodo(id)
            }
        }
    }
}
</script>

<style>
/*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;
    }

    li:hover{
        background-color: #ddd;
    }

    li:hover button{
        display: block;
    }
</style>

MyFooter.vue

<template>
    <div class="todo-footer" v-show="total">
        <label>
        <input type="checkbox" :checked="isAll" @change="checkAll"/>
        </label>
        <span>
        <span>已完成{
   
   {doneTotal}}</span> / 全部{
   
   {total}}
        </span>
        <button class="btn btn-danger" @click="clearAllTodo">清除已完成任务</button>
    </div>
</template>

<script>
export default {
    props:['todos','checkAllTodo','clearAllTodo'],
    computed:{
        total(){
            return this.todos.length
        },
        doneTotal(){
            // 使用ES6的reduce方法
            return this.todos.reduce((pre,current)=> pre + (current.done?1:0),0)
            // let i=0;
            // this.todos.forEach((todo) => {
            //     if(todo.done) i++
            // })
            // return i;
        },
        isAll(){
            // 注意：这里要加this
            return this.doneTotal === this.total && this.total>0
        }
    },
    methods:{
        // e就是使用该函数的对象，在这里是全选按钮checkbox
        checkAll(e){
            // 将全选按钮是否选择作为参数传递给checkAllTodo函数
            // 注意：这里要加this！！
            this.checkAllTodo(e.target.checked)
        },
        clearAll(){
            this.clearAllTodo()
        }
    }
}
</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>