Elementui form自定义正则

## Elementui form自定义正则

```javascript
businessCertNo: [
  { required: true, message: '请输入xxxxxxx', trigger: 'blur' },
  { validator: reg_businessCertNo, trigger: 'blur' },
],
  
  
export function reg_businessCertNo(rule, value, callback) {
  if (value === "") {
    callback(new Error("messge"));
  } else {
    var chrnum = /^\w{2,20}$/g;
    if (!chrnum.test(value)) {
      callback(new Error("message"));
    }
    callback();
  }
}
```