vue的filter如何調用function的方法？
vue的filter調用function有四種，可以自己編寫過濾器，實現內部過濾，注冊相關值，根據關鍵字過濾表的功能，實現對function的調用。
a: 2.0將1.0所有自帶的過濾器都刪除了，也就是說，在2.0中，要使用過濾器，則需要我們自己編寫。
b: 2.0過濾器的傳參方式不是以前的方式，是以函數傳參的方式，下面示例（后面有具體示例）：
之前調用: {{msg | mimi '12' '5'}}現在調用: {{msg | mimi('12','5')}}
c: 移除雙向過濾器：
Vue.filter('change', {
read: function (val) {
return val
},
write: function (val, oldVal) {
return isEmail(val) ? val : oldVal
}
})
1.組件內部過濾（此例子寫法適用于處理數據顯示的樣式，不會改變原數據）
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>filter</title>
<script src="https://unpkg.com/vue/dist/vue.js"></script>
</head>
<body>
<div id="app">
<ul>
<!--添加兩個過濾器,注意不要沖突,注意先后順序-->
<li v-for="item in list">{{item.id | filterAdd1 | filterAdd2}}</li>
</ul>
</div>
</body>
<script>
var vm = new Vue({
el:'#app',
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+10;
},
filterAdd2(item) {
return '$'+item;
}
},
methods:{
},
mounted(){
}
})
</script>
</html>
2.注冊在全局的fliter，filter傳值，filter動態傳值
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>filter</title>
<script src="https://unpkg.com/vue/dist/vue.js"></script>
</head>
<body>
<div id="app">
<ul>
<!--添加兩個過濾器,注意不要沖突,注意先后順序-->
<!-- 過濾傳值，帶引號的是字符串，不帶是number,傳的值可以動態綁定-->
<li v-for="item in list">{{item.id | filterAdd1(Number(input),20) | filterAdd2}}</li>
</ul>
<input type="text" placeholder="place" v-model="input">
</div>
</body>
<script>
Vue.filter('filterAdd1', function (value,one,two) {
return value+one+two;//默認第一個參數就是默認要過濾的那個值
})
Vue.filter('filterAdd2', function (value) {
return '$'+value;
})
var vm = new Vue({
el:'#app',
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>
</html>
結果：
3. 計算屬性篩選，methods方法篩選
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<!-- <script src="vue.js"></script> -->
<script src="https://unpkg.com/vue/dist/vue.js"></script>
</head>
<body>
<div id="app">
<div @click="addMore">加載更多</div>
<ul><li v-for="item in filterlist">{{item}}</li></ul>
<hr>
<ul><li v-for="item in filterlistFun()">{{item}}</li></ul>
</div>
</body>
<script>
var vm = new Vue({
el:'#app',
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":"55555"},
{"id":5,"title":"66666","cont":"66666"},
{"id":6,"title":"77777","cont":"77777"},
{"id":7,"title":"77777","cont":"88888"},
{"id":8,"title":"888888","cont":"999999"},
{"id":9,"title":"000000","cont":"99999"},
{"id":10,"title":"a88888","cont":"99999"},
{"id":11,"title":"a22222","cont":"111111"},
{"id":12,"title":"a33333","cont":"111111"},
{"id":13,"title":"a44444","cont":"111111"},
{"id":14,"title":"a55555","cont":"55555"},
{"id":15,"title":"a66666","cont":"66666"},
{"id":16,"title":"a77777","cont":"77777"},
{"id":17,"title":"a77777","cont":"88888"},
{"id":18,"title":"a888888","cont":"999999"},
{"id":19,"title":"a000000","cont":"99999"},
{"id":20,"title":"a88888","cont":"99999"}
]
}
},
computed: {
filterlist () {
let num=this.size;
return this.list.filter(function (number) {
return number.id < num
})
}
},
methods:{
filterlistFun(val){
let num=this.size;
return this.list.filter(function (number) {
return number.id < num
})
},
addMore(){
this.size+=5;
},
},
mounted(){
}
})
</script>
</html>
4.使用js中的迭代函數filter
實例一原文
var app5 = new Vue({
el: '#app5',
data: {
shoppingList: [
"Milk", "Donuts", "Cookies", "Chocolate", "Peanut Butter", "Pepto Bismol", "Pepto Bismol (Chocolate flavor)", "Pepto Bismol (Cookie flavor)"
],
key: ""
},
computed: {
filterShoppingList: function () {
// `this` points to the vm instance
var key = this.key;
var shoppingList = this.shoppingList;
//在使用filter時需要注意的是，前面調用的是需要使用filter的數組，而給filter函數傳入的是數組中的每個item，也就是說filter里面的函數，是每個item要去做的，并將每個結果返回。
return shoppingList.filter(function (item) {
return item.toLowerCase().indexOf(key.toLowerCase()) != -1
});;
}
}
})
<ul>
Filter Key<input type="text" v-model="key">
<li v-for="item in filterShoppingList">
{{ item }}
</li>
</ul>
最終效果實現了根據關鍵字來過濾列表的功能。
其他的一些Js 迭代方法——filter()、map()、some()、every()、forEach()、lastIndexOf()、indexOf()
