如何使用组件和v-bind筛选Vue中的posts :类

Question

我试着用我从这里得到的笔做一个例子：https://codepen.io/conradolandia/pen/YzyPmrv

但是我想使用vue路由器，我已经尝试过了：(pen：https://codepen.io/conradolandia/pen/vYNERPW)

HTML：

<main class="wrap">
    <div id="app">
        <router-view></router-view>
    </div>
</main>

<template id="post-list-template">
    <div class="container">
        <div class="row">
            <h4>Filter by album:</h4>
            <div class="filters">
                <button class="btn" v-bind:class="{ active: currentFilter === 'ALL' }" v-on:click="setFilter('ALL')">all</button>
                <button class="btn" v-bind:class="{ active: currentFilter === 'art' }" v-on:click="setFilter('art')">art</button>
                <button class="btn" v-bind:class="{ active: currentFilter === 'doodles' }" v-on:click="setFilter('doodles')">doodles</button>
                <button class="btn" v-bind:class="{ active: currentFilter === 'workshops' }" v-on:click="setFilter('workshops')">workshops</button>
            </div>
        </div>
        <div class="columns is-multiline">
            <div class="column is-3" v-if="currentFilter === post.category || currentFilter === 'ALL'" v-bind:key="post.title" v-for="post in posts">
                <div class="card post">
                    <img class="card-img-top" v-bind:src="post.image">
                    <div class="card-body">
                        <div class="card-title">{{ post.title }}</div>
                        <small class="tags">{{ post.category }}</small>
                    </div>
                </div> <!-- .post -->
            </div> <!-- .col-md-4 -->
        </div> <!-- .row -->
    </div> <!-- .container -->
</template>

CSS：

body{
    background-color: #ccc;
    box-sizing:border-box;
    -webkit-box-sizing:border-box;
    -moz-box-sizing:border-box;
}

.post {
    margin-bottom: 20px;
}

.post img{ width: 100%;}

.tags {background-color: #ccc; padding: 3px 5px;}

.filters {
    margin-bottom: 20px;
}

联署材料：

var postList = Vue.extend({

    template: "#post-list-template",

    data: function(){
        return {
            currentFilter:'ALL',
            posts: [
                {title: "Artwork", image: "https://picsum.photos/g/200?image=122", category: 'art'},
                {title: "Charcoal", image: "https://picsum.photos/g/200?image=116", category: 'art'},
                {title: "Sketching", image: "https://picsum.photos/g/200?image=121", category: 'doodles'},
                {title: "Acrillic", image: "https://picsum.photos/g/200?image=133", category: 'workshops'},
                {title: "Pencil", image: "https://picsum.photos/g/200?image=134", category: 'doodles'},
                {title: "Pen", image: "https://picsum.photos/g/200?image=115", category: 'art'},
                {title: "Inking", image: "https://picsum.photos/g/200", category: 'workshops'},
                {title: "Artwork", image: "https://picsum.photos/g/200?image=121", category: 'art'},
                {title: "Charcoal", image: "https://picsum.photos/g/200?image=115", category: 'art'},
                {title: "Sketching", image: "https://picsum.photos/g/200?image=124", category: 'doodles'},
                {title: "Acrillic", image: "https://picsum.photos/g/200?image=13", category: 'workshops'},
                {title: "Pencil", image: "https://picsum.photos/g/200?image=14", category: 'doodles'},
            ]
        }
    },
    methods: {
        setFilter: function(filter) {
            this.currentFilter = filter;
        }
    },
})

// Start a new instance of router (instead of router.map)
var router = new VueRouter({
    routes: [
        { path: '/', component: postList }
    ]
})

// Start a new instance of the Application required (instead of router.start)
new Vue({
    el: '#app',
    router: router,
})

到目前为止，还没有运气。过滤类工作，第一次单击I就激活了一个筛选选项，但随后所有过滤器都停止工作，火狐抱怨说"TypeError: e是未定义的“。

有人能给我指明正确的方向吗？我不明白为什么第一个代码链接工作，但第二个不工作。

澄清:当我点击任何过滤器，过滤某种工作，但如果我点击“所有”过滤器，一切停止工作。

Answer 1

尝试使用计算函数

computed:{
  filteredPosts:function(){
    if(this.currentFilter==='ALL'){
       return this.posts;
    }
    return this.posts.filter(post=>{
      return post.category === this.currentFilter;
    })
  }
}

循环时可以使用filteredPosts而不是posts

    <div class="columns is-multiline">
        <div class="column is-3" :key="post.title" v-for="post in filteredPosts">
            <div class="card post">
                <img class="card-img-top" :src="post.image">
                <div class="card-body">
                    <div class="card-title">{{ post.title }}</div>
                    <small class="tags">{{ post.category }}</small>
                </div>
            </div> <!-- .post -->
        </div> <!-- .col-md-4 -->
    </div> <!-- .row -->

您不需要在循环时使用任何条件，因为computed函数将完成这项工作。