$emit("input")小例子

<template>
    <div>
        <div class="group">
            <label>{{title}}</label>
            <input type="text" placeholder="请输入" @input="changeData()" v-model="val">
        </div>
    </div>
</template>

<script>
export default {
    props:["title"],
    data () {
        return {
            val:""
        }
    },
    methods:{
        changeData:function(){
            console.log(111);
            this.$emit(‘input‘,this.val);
        }
    }
}
</script>

<cmsGroup title="用户名" v-model="username"></cmsGroup>