组件是vue最核心的功能，组件化你的前端页面，能大大的提高重用性，让代码可复用，维护起来简直爽的飞起，举例来说就比如一些评论输入框。
在vue中使用组件
Vue.component('input-number',{
template:'\
<div class="input-number">\
<input type="text" @focus="focusEvent" @blur="blurEvent" @keydown="keyEvent" :value="currentValue" @change="handleChange">\
<button @click="handleDown" :disabled="currentValue <= min">-</button>\
<button @click="handleUp" :disabled="currentValue >= max">+</button>\
</div>\
',
props:{
max:{
type:Number,
default:Infinity
},
min:{
type:Number,
default:-Infinity
},
value:{
type:Number,
default:0
},
step:{
type:Number,
default:1
}
},
data:function(){
return {
currentValue:this.value,
isfocus:false
}
},
watch:{
currentValue:function(val){
this.$emit('input',val);
this.$emit('on-change',val);
},
value:function(val){
this.updateValue(val);
}
},
methods:{
updateValue:function(val){
if(val>this.max)val = this.max;
if(val<this.min)val = this.min;
this.currentValue = val;
},
handleDown:function(){
if(this.currentValue<=this.min)return;
this.currentValue-=this.step;
},
handleUp:function(){
if(this.currentValue>=this.max)return;
this.currentValue+=this.step;
},
handleChange:function(event){
var val = event.target.value.trim();
var max = this.max;
var min = this.min;
if(isValueNumber(val)){
val = Number(val);
this.currentValue = val;
if(val>max){
this.currentValue = max;
}else if(val<min){
this.currentValue = min;
}
}else{
event.target.value = this.currentValue;
}
},
focusEvent:function(event){
this.isfocus = true;
},
blurEvent:function(event){
this.isfocus = false;
},
keyEvent:function(event){
if(this.isfocus){
if(event.keyCode == 38){
// 上方向键
this.handleUp();
}else if(event.keyCode == 40){
// 下方向键
this.handleDown();
}
}
}
},
mounted:function(){
this.updateValue(this.value);
}
})
function isValueNumber (value){
return (/(^-?[0-9]+\.{1}\d+$)|(^-?[1-9][0-9]*$)|(^-?0{1}$)/).test(value);
}
引入插件
<input-number v-model="value" :max="10" :min="0" :step="2">
