<div id="app">
  <ol>
    <li v-for="company in companies">
      <a v-bind:href="company.link">{{ company.text }}</a>  // bind 更新参数
            <button v-on:click="reverseText">逆转消息</button>
    </li>
  </ol>
</div>

let vm = new Vue({
    el: '#app',
        data: {
            companies: [
                    {text: 'Google', link: 'http://google.com'},
                        {text: 'fackbook', link: 'http://facebook.com'},
                        {text: 'apple', link: 'http://apple.com'}
                ]
        },
        methods: {
            reverseText: function() {
            // 注意 this 绑定到了触发这个事件的元素内部
                    this.company.text = this.company.text.split('').reverse.join('');
                }
        }   
});

vm.companies.push({text: 'Amazon', link: 'http://amazon.com'});

// computed 属性可以绑定一个虚拟的属性到几个不同的属性上, 有点类似python的@property
// ...
computed: {
  fullName: {
    // getter
    get: function () {
      return this.firstName + ' ' + this.lastName
    },
    // setter
    set: function (newValue) {
      var names = newValue.split(' ')
      this.firstName = names[0]
      this.lastName = names[names.length - 1]
    }
  }
}
// ...

# 适合用来做自动保存文档等工作
<script>
var watchExampleVM = new Vue({
  el: '#watch-example',
  data: {
    question: '',
    answer: 'I cannot give you an answer until you ask a question!'
  },
  watch: {
    // 如果 question 发生改变，这个函数就会运行
    question: function (newQuestion) {
      this.answer = 'Waiting for you to stop typing...'
      this.getAnswer()
    }
  },
  methods: {
    // _.debounce 是一个通过 lodash 限制操作频率的函数。
    // 在这个例子中，我们希望限制访问 yesno.wtf/api 的频率
    // ajax 请求直到用户输入完毕才会发出
    // 学习更多关于 _.debounce function (and its cousin
    // _.throttle)，参考：https://lodash.com/docs#debounce
    getAnswer: _.debounce(
      function () {
        if (this.question.indexOf('?') === -1) {
          this.answer = 'Questions usually contain a question mark. ;-)'
          return
        }
        this.answer = 'Thinking...'
        var vm = this
        axios.get('https://yesno.wtf/api')
          .then(function (response) {
            vm.answer = _.capitalize(response.data.answer)
          })
          .catch(function (error) {
            vm.answer = 'Error! Could not reach the API. ' + error
          })
      },
      // 这是我们为用户停止输入等待的毫秒数
      500
    )
  }
})
</script>

<template v-if="ok">
  <h1>Title</h1>
  <p>Paragraph 1</p>
  <p>Paragraph 2</p>
</template>

<button v-on:click="warn('Form cannot be submitted yet.', $event)">
  Submit
</button>

<a v-bind:href="url">{{ link_text }}</a>

<!-- 完整语法 -->
<a v-bind:href="url"></a>
<!-- 缩写 -->
<a :href="url"></a>

<!-- 完整语法 -->
<a v-on:click="doSomething"></a>
<!-- 缩写 -->
<a @click="doSomething"></a>

<div id="app-6">
  <p>{{ message }}</p>
  <input v-model="message">
</div>

var app6 = new Vue({
  el: '#app-6',
  data: {
    message: 'Hello Vue!'
  }
})

<span>Multiline message is:</span>
<p style="white-space: pre-line;">{{ message }}</p>
<br>
<textarea v-model="message" placeholder="add multiple lines"></textarea>

// 在vue中注册一个组件, 大多数传递给vue实例的参数都可以使用, 除了 data 必须是一个函数

Vue.component('todo-item', {
  // todo-item 组件现在接受一个"prop"，类似于一个自定义属性. 这个属性名为 todo。
  props: ['todo'],
  template: '<li>{{ todo.text }}</li>',
  data: function() {},
})

<div id="app-7">
  <ol>
    <!-- 现在我们为每个todo-item提供待办项对象    -->
    <!-- 待办项对象是变量，即其内容可以是动态的 -->
    <todo-item v-for="item in groceryList" v-bind:todo="item"></todo-item>
  </ol>
</div>

Vue.component('todo-item', {
  props: ['todo'],
  template: '<li>{{ todo.text }}</li>'
})
var app7 = new Vue({
  el: '#app-7',
  data: {
    groceryList: [
      { text: '蔬菜' },
      { text: '奶酪' },
      { text: '随便其他什么人吃的东西' }
    ]
  }
})

<div id="counter-event-example">
  <p>{{ total }}</p>
  <button-counter v-on:increment="incrementTotal"></button-counter>
  <button-counter v-on:increment="incrementTotal"></button-counter>
</div>
Vue.component('button-counter', {
  template: '<button v-on:click="incrementCounter">{{ counter }}</button>',
  data: function () {
    return {
      counter: 0
    }
  },
  methods: {
    incrementCounter: function () {
      this.counter += 1
      this.$emit('increment')
    }
  },
})
new Vue({
  el: '#counter-event-example',
  data: {
    total: 0
  },
  methods: {
    incrementTotal: function () {
      this.total += 1
    }
  }
})

<div id="app">
  <p>
    <router-link to="/user/foo">/user/foo</router-link>
    <router-link to="/user/bar">/user/bar</router-link>
  </p>
  <router-view></router-view>
</div>

<script>
const User = {
  template: `<div>User {{ $route.params.id }}</div>`
}

const router = new VueRouter({
  mode: 'history',  // 这样才能使用 html5 的history api
  routes: [
    { path: '/user/:id', component: User }
  ]
})

const app = new Vue({ router }).$mount('#app')
</script>