Angular 2 Final中的最小/最大验证器

问题描述

根据 thoughtgram.io ，当前支持的验证器为:

According to thoughtgram.io, the currently supported validators are:

• 必填
• 最小长度
• 最大长度
• 模式

因此，请考虑以下代码(在此处插入代码):

So, considering the following code (plunkr here):

@Component({
  selector: 'my-app',
  template: `

  <form #formRef="ngForm">
    <input type="number" [(ngModel)]="firstValue" name="firstValue" min="0" required/>
    <input type="text" [(ngModel)]="secondValue" maxlength="5" name="secondValue" required/>
    <button type="submit"> Submit </button>
  </form>

  FORM: {{formRef.form | json }}
`
})
export class AppComponent {
  firstValue = -22;
  secondValue = "eyy macarena!";
}

虽然支持minlength，但是min="0"被角度验证忽略:

While minlength is supported, min="0" is ignored by angular validation:

因此，当firstValue ngModel<时，使表单导致错误. 0，我需要构建自定义验证器吗?

So, to make the form result in an error when firstValue ngModel < 0, do I need to build a custom validator?

推荐答案

要将min/max validation应用于number，您将需要创建Custom Validator

To apply min/max validation on a number you will need to create a Custom Validator

Validators 类目前仅有几个验证器，即

Validators class currently only have a few validators, namely

• 必填
• requiredTrue
• 最小长度
• 最大长度
• 模式
• nullValidator
• 撰写
• composeAsync

• required
• requiredTrue
• minlength
• maxlength
• pattern
• nullValidator
• compose
• composeAsync

验证器: 以下是我的数字验证器的简化版本，您可以根据需要对其进行改进

static number(prms = {}): ValidatorFn {
    return (control: FormControl): {[key: string]: string} => {
      if(isPresent(Validators.required(control))) {
        return null;
      }

      let val: number = control.value;

      if(isNaN(val) || /\D/.test(val.toString())) {

        return {"number": true};
      } else if(!isNaN(prms.min) && !isNaN(prms.max)) {

        return val < prms.min || val > prms.max ? {"number": true} : null;
      } else if(!isNaN(prms.min)) {

        return val < prms.min ? {"number": true} : null;
      } else if(!isNaN(prms.max)) {

        return val > prms.max ? {"number": true} : null;
      } else {

        return null;
      }
    };
  }

用法:

// check for valid number
var numberControl = new FormControl("", [Validators.required, CustomValidators.number()])

// check for valid number and min value
var numberControl = new FormControl("", CustomValidators.number({min: 0}))

// check for valid number and max value
var numberControl = new FormControl("", CustomValidators.number({max: 20}))

// check for valid number and value range ie: [0-20]
var numberControl = new FormControl("", CustomValidators.number({min: 0, max: 20}))

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