[verification] only numbers (positive and negative numbers) can be entered

 var validate = (rule, val, callback) => {
        if (!val) {
          callback(new Error(' Please enter '))
        } else {
          const reg = /^[+-]?(0|([1-9]\d*))(\.\d+)?$/
          if (reg.test(val)) {
            return callback()
          } else {
            callback(new Error(' Input format error '))
          }
        }
      }

Enter positive and negative numbers