vue filter 学习笔记

vue中过滤器Filter

1、组件内部过滤(此例写法适用于处理数据显示的样式，不会改变原数据)

<div id="app1">
    <ul>

        <li v-for="item in list">{{  item.id | filterAdd1 | filterAdd2 }}li> 
    
    ul>
div>
<script>
    const app1 = new Vue({
        el: '#app1',
        data() {
            return {
                list: [
                    {"id":0,"title":"11111","cont":"111111"},
                    {"id":1,"title":"22222","cont":"111111"},
                    {"id":2,"title":"33333","cont":"111111"},
                    {"id":3,"title":"44444","cont":"111111"},
                ]
            }
        },
        filters: {
            filterAdd1(item) {
                return item + 1;
            },
            filterAdd2(item) {
                return '$' + item;
            }
        },
        methods: {

        },
        mounted() {

        }
    })
script>

2、注册在全局的filter，filter传值，filter动态传值

<div id="app2">
    <ul>
        
        
        <li v-for="item in list">{{item.id | filterAdd1(Number(input),20) | filterAdd2}}li>
    ul>
    <input type="text" placeholder="place" v-model="input">
div>
<script>
    Vue.filter('filterAdd1', function (value,one,two) {
        return value+one+two;//默认第一个参数就是默认要过滤的那个值
    })
    Vue.filter('filterAdd2', function (value) {
        return '$'+value;
    })
    var vm = new Vue({
        el:'#app2',
        data(){
            return {
                input:5,
                list:[
                    {"id":0,"title":"11111","cont":"111111"},
                    {"id":1,"title":"22222","cont":"111111"},
                    {"id":2,"title":"33333","cont":"111111"},
                    {"id":3,"title":"44444","cont":"111111"},
                ]
            }
        },
        methods:{
        },
        mounted(){
        }
    })
script>

3、计算属性筛选，methods方法筛选

<div id="app3">
    <div @click="addMore">加载更多div>
    <ul><li v-for="item in filterlist">{{item}}li>ul>
    <hr>

div>
<script>
    var vm = new Vue({
        el:'#app3',
        data(){
            return {
                size:5,
                list:[
                    {"id":0,"title":"11111","cont":"111111"},
                    {"id":1,"title":"22222","cont":"111111"},
                    {"id":2,"title":"33333","cont":"111111"},
                    {"id":3,"title":"44444","cont":"111111"},
                    {"id":4,"title":"55555","cont":"555555"},
                    {"id":5,"title":"66666","cont":"666666"},
                    {"id":6,"title":"77777","cont":"777777"},
                    {"id":7,"title":"77777","cont":"888878"},
                    {"id":8,"title":"88888","cont":"999999"},
                    {"id":9,"title":"000000","cont":"99999"},
                    {"id":10,"title":"88888","cont":"99999"},
                    {"id":11,"title":"a2222","cont":"11111"},
                    {"id":12,"title":"a3333","cont":"11111"},
                    {"id":13,"title":"a4444","cont":"11111"},
                    {"id":14,"title":"a5555","cont":"55555"},
                    {"id":15,"title":"a6666","cont":"66666"},
                    {"id":16,"title":"a7777","cont":"77777"},
                    {"id":17,"title":"a7777","cont":"88888"},
                    {"id":18,"title":"a8888","cont":"99999"},
                    {"id":19,"title":"a0000","cont":"99999"},
                    {"id":20,"title":"a8888","cont":"99999"}
                ]
            }
        },
        // 计算属性筛选
        computed: {
            filterlist () {
                let num=this.size;
                return this.list.filter(function (number) {
                    return number.id < num
                })
            }
        },
        methods:{
            // methods方法筛选
            // filterlistFun(val){
            //     let num=this.size;
            //     return this.list.filter(function (number) {
            //         return number.id < num
            //     })
            // },
            addMore(){
                this.size+=5;
            },
        },
        mounted(){
        }
    })
script>

4、使用js中的迭代函数filter

filter():对数组中的每一项运行给定函数，返回该函数会返回true的项组成的数据

<div id="app4">
    <ul>
        Filter Key<input type="text" v-model=" searchValue">
        <li v-for="item in filterShoppingList">
            {{ item }}
        li>
    ul>
div>
<script>
    const app4 = new Vue({
        el: '#app4',
        data: {
            shoppingList: [
                "Milk", "Donuts", "Cookies", "Chocolate", "Peanut Butter", "Pepto Bismol", "Pepto Bismol (Chocolate flavor)", "Pepto Bismol (Cookie flavor)"
            ],
            searchValue: ""
        },
        computed: {
            filterShoppingList() {
                var  searchValue = this. searchValue;
                var shoppingList = this.shoppingList;
                //在使用filter时需要注意的是，前面调用的是需要使用filter的数组，而给filter函数传入的是数组中的每个item，也就是说filter里面的函数，是每个item要去做的，并将每个结果返回。
                return shoppingList.filter(function (item) {
                    return item.toLowerCase().indexOf(searchValue.toLowerCase()) != -1
                });
            }
        }
    })
script>