老师怎么简化watch中的函数，能不能复用methods中的函数

来源：3-23 自由编程

松_松

2020-09-14 09:46:39

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>计算器</title>
<style>
#app{
padding-top: 300px;
padding-left: 500px;
}
</style>
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<div id="app">
<input type="text" v-model.number="num1">
<select v-model="fuhao">
<option>+</option>
<option>-</option>
<option>*</option>
<option>/</option>
</select>
<input type="text" v-model.number="num2">
<button @click="js">=</button>
<input type="text" v-model.number="jg">
</div>
<script>
var vm = new Vue({
el: "#app",
data: {
num1:'',
fuhao:'+',
num2:'',
jg:"",
},
methods:{
js: function () {
switch (this.fuhao) {
case "+":
this.jg=this.num1+this.num2;
break;
case "-":
this.jg=this.num1-this.num2;
break;
case "*":
this.jg=this.num1*this.num2;
break;
case "/":
this.jg=this.num1/this.num2;
break;

}
}
},
watch:{
fuhao :function () {
switch (this.fuhao) {
case "+":
this.jg=this.num1+this.num2;
break;
case "-":
this.jg=this.num1-this.num2;
break;
case "*":
this.jg=this.num1*this.num2;
break;
case "/":
this.jg=this.num1/this.num2;
break;

}
}
}
});

</script>
</body>
</html>