<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
table {
width: 600px;
color: #8f8e8e;
text-align: center;
border-collapse: collapse;
}
table thead {
background: #F5F5F5;
}
table tr {
height: 30px;
line-height: 30px;
border: 1px solid #ececec;
}
</style>
</head>
<body>
<div id="app">
<table>
<thead>
<tr>
<!-- <td><input type="checkbox" v-model="data.selected" @change="selectAll" /></td> -->
<td><input type="checkbox" v-model="data.selected" /></td>
<td>商品</td>
<td>单价</td>
<td>库存</td>
<td colspan="2">操作</td>
</tr>
</thead>
<tbody>
<tr v-for="(value, index) in data.list">
<!--
<td><input type="checkbox" v-model="data.checkboxList" :value="value" @change="checkSelect" /></td>
-->
<td><input type="checkbox" v-model="data.checkboxList" :value="value" /></td>
<td>{{ value.name }}</td>
<td>{{ value.price }}</td>
<td>{{ value.stock }}</td>
<td>
<button @click="sub(value)">-</button>
{{ value.number }}
<button @click="add(value)">+</button>
</td>
<td><button @click="del(index,value.id)">删除</button></td>
</tr>
</tbody>
<tfoot>
<tr>
<!-- <td>总价 {{ totalPrice() }}</td> -->
<td>总价 {{ totalPrice }}</td>
</tr>
</tfoot>
</table>
</div>
<script type="module">
import { createApp, reactive, watch, computed } from './vue.esm-browser.js'
createApp({
setup() {
const data = reactive({
selected: false,
checkboxList: [],
list: [{
id: 1,
name: "铅笔",
price: 10,
number: 1,
stock: 3
},
{
id: 2,
name: "鼠标",
price: 20,
number: 2,
stock: 5
},
{
id: 3,
name: "键盘",
price: 30,
number: 1,
stock: 6
}],
})
//减
const sub = (value) => {
value.number--
if (value.number <= 1) {
value.number = 1
}
}
//加
const add = (value) => {
value.number++
if (value.number >= value.stock) {
value.number = value.stock
}
}
//删除
const del = (index, id) => {
data.list.splice(index, 1) //splice(要删除元素的索引位置, 要删除的元素数量)
//filter 筛选符合条件的元素, 返回一个新的数组
let newArr = data.checkboxList.filter((value, index) => {
return value.id != id
})
data.checkboxList = newArr
//checkSelect() //检查勾选状态
}
/*
//总价
const totalPrice = () => {
let total = 0
for (let i = 0; i < data.checkboxList.length; i++) {
total += data.checkboxList[i].price * data.checkboxList[i].number
}
return total
}
*/
//计算属性-有缓存 [计算属性根据其依赖的响应式数据变化而重新计算]
const totalPrice = computed(() => {
/*
reduce定义: 用于对数组中的所有元素进行迭代操作, 并将每次操作的结果累加到一个初始值上
reduce接收两个参数: 一个是累加器函数, 另一个是初始值
reduce: 将 data.checkboxList 数组中的每个 checkbox 对象的 price 和 number 属性进行相乘,
并将结果累加到初始值 0 上, 最后返回累加的结果
total(累加器) 用于存储每次计算的结果, 初始值为 0
item(当前元素) 在每次迭代过程中, 当前元素的值会被传递给回调函数
*/
return data.checkboxList.reduce((total, item) => total + item.price * item.number, 0)
})
/*
//全选/反选
const selectAll = () => {
if (data.selected) { //true
data.checkboxList = data.list
} else { //false
data.checkboxList = []
}
}
*/
//监听 data.selected
let flag = true
watch(() => data.selected, (newValue, oldValue) => {
//console.log("newValue:",newValue,"oldValue:",oldValue)
if (newValue) {
data.checkboxList = data.list
} else {
if (flag) {
data.checkboxList = []
}
}
//console.log(data.checkboxList)
})
/*
//检查勾选状态
const checkSelect = () => {
if (data.checkboxList.length == data.list.length && data.list.length != 0) {
data.selected = true
} else {
data.selected = false
}
}
*/
//监听 data.checkboxList
watch(() => data.checkboxList, (newValue, oldValue) => {
console.log("newValue:", newValue, "oldValue:", oldValue)
console.log(newValue.length)
if (newValue.length == data.list.length && data.list.length != 0) {
data.selected = true
flag = true
} else {
data.selected = false
flag = false
}
})
return {
data,
sub,
add,
del,
totalPrice,
//selectAll,
//checkSelect
}
}
}).mount("#app")
</script>
</body>
</html>
5.购物车优化案例
-- 未经授权禁止转载 --