实现效果

代码

template部分

<el-input v-model="state.val"></el-input><div>{{ priceFor(state.val) }}</div>

js部分

const state = reactive({
val:''
});const priceFor = (val)=> {if(!val){return ''}else if(val.length<4){return val}else {let str = val+''let numList = []for(let i = 1;i<=str.length;i=i+0){if(str.length>=4){numList.unshift(str.substring(str.length - 3, str.length))str = str.slice(0, -3)}else {numList.unshift(str)str = ''}}return numList.join(',')}
}