model校验

对v-model进行实时校验

computed: {
    modelErrors () {
        let errorMsg, status
        if (!/@/g(某种正则).test(this.username)) {
            status = false
            errorMsg = '${sth}'
        }
        else {
            sth
        }
        return {
            status,
            errorMsg
        }
    }
}