Vue学习-01
1.vue 学习
v-bind:title 数据绑定
v-if 判断显示或者隐藏
<div id="app-3">
<p v-if="seen">Now you see me</p>
</div>
v-for 循环
<div id="app-4">
<ol>
<li v-for="todo in todos">
{{ todo.text }}
</li>
</ol>
</div>
v-on 事件绑定
<div id="app-5">
<p>{{ message }}</p>
<button v-on:click="reverseMessage">Reverse Message</button>
</div>
var app5 = new Vue({
el: '#app-5',
data: {
message: 'Hello Vue.js!'
},
methods: {
reverseMessage: function () {
this.message = this.message.split('').reverse().join('')
}
}
})
v-model 双向数据绑定
<div id="app-6">
<p>{{ message }}</p>
<input v-model="message">
</div>
var app6 = new Vue({
el: '#app-6',
data: {
message: 'Hello Vue!'
}
})
组件
<div id="app-7">
<ol>
<!-- Now we provide each todo-item with the todo object -->
<!-- it's representing, so that its content can be dynamic -->
<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: 'Vegetables' },
{ text: 'Cheese' },
{ text: 'Whatever else humans are supposed to eat' }
]
}
})
2.vue实例
属性和方法
每个 Vue 实例都会代理其 data 对象里所有的属性
var data = { a: 1 }
var vm = new Vue({
data: data
})
vm.a === data.a // -> true
// 设置属性也会影响到原始数据
vm.a = 2
data.a // -> 2
// ... 反之亦然
data.a = 3
vm.a // -> 3
生命周期
beforeCreate->created->beforeMount->mounted->beforeUpdate->updated->beforeDestroy->destroyed
3.模板语法
插值（文本，纯html，属性，javascript表达式）
指令（参数，修饰符）
Filters（过滤器）
缩写（v-bind，v-on）
4.计算属性
基础例子
<div id="example">
<p>Original message: "{{ message }}"</p>
<p>Computed reversed message: "{{ reversedMessage }}"</p>
</div>
var vm = new Vue({
el: '#example',
data: {
message: 'Hello'
},
computed: {
// a computed getter
reversedMessage: function () {
// `this` points to the vm instance
return this.message.split('').reverse().join('')
}
}
})
计算缓存vs Methods
如果没有缓存，我们将不可避免的多次执行 A 的 getter ！如果你不希望有缓存，请用 method 替代。
<p>Reversed message: "{{ reverseMessage() }}"</p>
// in component
methods: {
reverseMessage: function () {
return this.message.split('').reverse().join('')
}
}
计算setter
// ...
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]
}
}
}
// ...
代码段
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
<title>Vue 起步</title>
</head>
<body>
<div id="app">
{{ message }}
</div>
<div id="app-2">
<span v-bind:title="message">
Hover your mouse over me for a few seconds to see my dynamically bound title!
{{ message }}
</span>
</div>
<div id="app-3">
<p v-if="seen">Now you see me</p>
</div>
<div id="app-4">
<ol>
<li v-for="todo in todos">
{{ todo.text }}
</li>
</ol>
</div>
<div id="app-5">
<p>{{ message }}</p>
<button v-on:click="reverseMessage">Reverse Message</button>
</div>
<div id="app-6">
<p>{{ message }}</p>
<input v-model="message">
</div>
<div id="app-7">
<ol>
<!-- Now we provide each todo-item with the todo object -->
<!-- it's representing, so that its content can be dynamic -->
<todo-item v-for="item in groceryList" v-bind:todo="item"></todo-item>
</ol>
</div>
<div id="example">
<p>Original message: "{{ message }}"</p>
<p>Computed reversed message: "{{ reverseMessage() }}"</p>
</div>
<div id="watch-example">
<p>
Ask a yes/no question:
<input v-model="question">
</p>
<p>{{ answer }}</p>
</div>
<script src="https://unpkg.com/vue/dist/vue.js"></script>
<script src="https://unpkg.com/axios@0.12.0/dist/axios.min.js"></script>
<script src="https://unpkg.com/lodash@4.13.1/lodash.min.js"></script>
<script>
var app = new Vue({
el: '#app',
data: {
message: 'Hello Vue!'
}
})
var app2 = new Vue({
el: '#app-2',
data: {
message: 'You loaded this page on ' + new Date()
}
})
var app3 = new Vue({
el: '#app-3',
data: {
seen: true
}
})
var app4 = new Vue({
el: '#app-4',
data: {
todos: [
{ text: 'Learn JavaScript' },
{ text: 'Learn Vue' },
{ text: 'Build something awesome' }
]
}
})
var app5 = new Vue({
el: '#app-5',
data: {
message: 'Hello Vue.js!'
},
methods: {
reverseMessage: function () {
this.message = this.message.split('').reverse().join('')
}
}
})
var app6 = new Vue({
el: '#app-6',
data: {
message: 'Hello Vue!'
}
})
Vue.component('todo-item', {
props: ['todo'],
template: '<li>{{ todo.text }}</li>'
})
var app7 = new Vue({
el: '#app-7',
beforeCreate:function(){
console.log('before');
},
data: {
groceryList: [
{ text: 'Vegetables' },
{ text: 'Cheese' },
{ text: 'Whatever else humans are supposed to eat' }
]
}
})
var vm = new Vue({
el: '#example',
data: {
message: 'Hello'
},
methods: {
// a computed getter
reverseMessage: function () {
// `this` points to the vm instance
return this.message.split('').reverse().join('')
}
}
})
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 () {
var vm = this
if (this.question.indexOf('?') === -1) {
vm.answer = 'Questions usually contain a question mark. ;-)'
return
}
vm.answer = 'Thinking...'
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>
</body>
</html>
