Vue syntax of Vue

Xu Wen 2020-11-09 19:11:29
vue syntax vue


( Remarks : The vue The arrangement of grammatical knowledge is based on vuejs Official documents are at the core , Assist some individual understanding or other case studies , So the article can't say original , Heaven is a fake original .)

Vue Basic grammar

vue example

let vm = new Vue({
el: '#app', // It means mounted DOM node
data: { // data If it's a single component data It's a function The data of each instance is not shared
message: 'hello vue!'
},
methods: { // Inside is vue Example method
}
)

interpolation

Text

When inserting a data For text parsing Use it directly {{}}

 <p>{{message}}</p> 
HTML

If the inserted data is carried out html analysis Use v-html

 <p v-html = 'msg'>{{msg}}</p> <!-- Corresponding vue In the instance data Variables of data -->
Node properties

When you need to add attributes to a node Use v-bind: You can use shorthand :

 <p v-bind:id = 'newId'></p> <!-- Corresponding vue In the instance data Variables of data -->

When the property value is Boolean , If false perhaps null perhaps undefined This property will not be rendered
All other values will default to true value ( Being is truth )

 <p :attr = 'attr'></p> <!-- Corresponding vue In the instance data Variables of data -->
`let app = new Vue({
el: '#app',
data: {
attr: false
}
})`
javaScript expression

In interpolation, except for data properties You can also put js expression

{{++num}}
{{name ? 'xuwen' : 'tom'}}

Instructions

With v- Attribute for prefix

  • v-html
  • v-bind: Abbreviation :
  • v-on: Abbreviation @
  • v-if
  • v-show
  • v-for
  • v-model

Dynamic properties

<span :[attrName]="attr"></span> <!-- Express attrName As a variable Take the value of the variable For attributes -->

The specific usage of these instructions is described in detail in the following chapters

v-for The list of rendering

It needs to be explained that Whether it's official or elsewhere v-for All of them are for in
I don't really understand If it is data Of the array I prefer to use for of The object uses for in
Only in this way can it be more semantic

<div id="app">
<div v-for="list of lists" :key="list.id">
{{ list.name }}
</div>
</div>
data() {
return {
name:'vuejs',
lists: [
{id:1, name:'xuwen'},
{id:2, name:' Wen Tianxiang '},
{id:3, name:' Su shi '}
]
}
}

stay v-for In block , We can access all of the parent scope's property

<div id="app">
<div v-for="list of lists" :key="list.id">
{{name}}-{{ list.name }}
</div>
</div>
a key :v-for There is key value , What does it do ?

answer : key The main function of value is to combine array elements with dom The nodes are bound together precisely ,
If you delete an element of an array vue It is to precisely delete the nodes related to it .
And if not key value vue More is node reuse If the data changes You'll compare the data one by one Waste performance

v-model Two way binding

v-model Mainly used in forms input textarea select Update data

 remarks : Be careful : v-model Ignore the form value,checked,selected The initial value of the , The data comes directly from data Value in 
<input type="text" v-model="inp">
<p>{{inp}}</p>
data(){
return {
inp: '123'
}
}
Check box

A single check box binds Boolean values

<!-- Check box -->
<input type="checkbox" name="checkbox" id="checkbox" v-model="checked">
<label for="checkbox">{{checked}}</label>

Multiple check boxes bind arrays

<input type="checkbox" name="" id="football" v-model="balls" value=" football ">
<label for="footabll"> football </label>
<input type="checkbox" name="" id="basketball" v-model="balls" value=" Basketball ">
<label for="basketball"> Basketball </label>
<input type="checkbox" name="" id="volleyball" v-model="balls" value=" Volleyball ">
<label for="volleyball"> Volleyball </label>
<p>{{balls}}</p>~~~~
 data() {
return {
checked: true,
balls: []
}
}
Radio button
<input type="radio" name="ball" id="football" v-model="ball" value=" football ">
<label for="footabll"> football </label>
<input type="radio" name="ball" id="basketball" v-model="ball" value=" Basketball ">
<label for="basketball"> Basketball </label>
<input type="radio" name="ball" id="volleyball" v-model="ball" value=" Volleyball ">
<label for="volleyball"> Volleyball </label>
<p>{{ball}}</p>
data() {
return {
ball: ''
}
}
Selection box
<select name="" id="" v-model="ball">
<option disabled value=""> Please select </option>
<option value=" football "> football </option>
<option value=" Basketball "> Basketball </option>
<option value=" Volleyball "> Volleyball </option>
</select>
<p>{{ball}}</p>
Modifier
<!-- Modifier -->
<!-- .lazy for example Update the data on both sides when entering -->
<input type="text" v-model.lazy = "message">
<!-- .number The numeric string entered is changed to the real numeric type -->
<input type="text" name="" id="" v-model.number = "num">
<!-- .trim Clear the space before and after -->
<input type="text" v-model.trim = "str">

v-on @ Event handling

<button @click = "addNum"> increase 1 individual </button>
<p>{{num}}</p>`
data() {
return {
num: 0
}
},
methods: {
addNum() {
this.num++;
}
}
Modifier
  • .stop
  • .prevent
  • .capture
  • .self
  • .once
  • .passive
  • .enter
  • .tab
  • .delete ( Capture “ Delete ” and “ Backspace ” key )
  • .esc
  • .space
  • .up
  • .down
  • .left
  • .right
  • .ctrl
  • .alt
  • .shift
  • .meta
v-if and v-show

v-if It's whether to render nodes or not
v-show Is whether the node is displayed false For hiding

class binding

commonly class Bind an object It contains whether a class exists

<div :class = "{active: isActive}"></div>
data(){
return {
isActive: true
}
}
版权声明
本文为[Xu Wen]所创,转载请带上原文链接,感谢

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