elementui el-input input number is an integer validation

elementui manual check digit is an integer

<script>
export default{
    data(){
        return {
            let checkNum = (rule,value,callback) => {
                if(!value) {
                    return new Error('必填信息')
                }else {
                    if(!Number.isInteger(value)) {
                        callback(new Error('请输入数字值'))
                    }else{
                        if(value < 0) {
                            callback(new Error('不能小于0'))
                        }else if(value > 20){
                            callback(new Error('不能大于20'))
                        }else {
                            callback()
                        }
                    }
                }
            }
            age: [{required: true,message:'必填信息'},{validator:checkNum,trigger:'blur'}]
        }
    }
}
</script>