数字输入框是对普通输入框的扩展，用来快捷输入一个标准的数字，如图：
代码：
<div id="app">
<input-number v-model="value" :max="100" :min="0"></input-number>
</div>
<script>
function isValueNumber (value) {
return (/(^-?[0-9]+\.{1}\d+$)|(^-?[1-9][0-9]*$)|(^-?0{1}$)/).test(value + '');
}
Vue.component('input-number', {
template: '\
<div class="input-number">\
<input \
type="text"\
:value="currentValue"\
@change="handleChange"\
@keyup.up="handleUp"\
@keyup.down="handleDown">\
<button \
@click="handleDown" \
:disabled="currentValue <= min">-</button> \
<button \
@click="handleUp" \
:disabled="currentValue >= max">+</button> \
</div>',
props: {
max: {
type: Number,
default: Infinity
},
min: {
type: Number,
default: -Infinity
},
value: {
type: Number,
default: 0
}
},
data: function() {
return {
currentValue: this.value
}
},
watch: {
currentValue: function (val) {
this.$emit('input', val);
this.$emit('on-change', val);
},
value: function (val) {
this.updateValue (val);
}
},
methods: {
handleDown: function () {
if(this.currentValue <= this.min) return;
this.currentValue -= 1;
},
handleUp: function () {
if(this.currentValue >= this.max) return;
this.currentValue += 1;
},
updateValue: function (val) {
if(val > this.max) val = this.max;
if(val < this.min) val = this.min;
this.currentValue = val;
},
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;
}
}
},
mounte: function () {
this.updateValue(this.value);
},
});
var app = new Vue({
el: '#app',
data: {
value: 5
}
})
</script>