angular5+ 自定义表单验证器

custom validators

标签（空格分隔）： angular

---

首先阐述一下遇到的问题：

• 怎样实现“再次输入密码”的验证（两个controller值相等）（equalto）
• 怎样反向监听（先输入“再次输入密码”，后输入设置密码）

解决思路：

• 第一个问题，可以通过[abstractcontrol].root.get([targetname])来取得指定的controller，然后比较他们的值。
• 第二个，可以通过[target].seterrors([errors])来实现。

1. 这是一个我的自定义表单验证：

import {abstractcontrol, formgroup, validatorfn} from '@angular/forms';
import {g} from '../services/data-store.service';

export class myvalidators {
  private static isemptyinputvalue(value) {
    // we don't check for string here so it also works with arrays
    return value == null || value.length === 0;
  }
  private static isemptyobject(obj) {
    if (typeof obj === 'object' && typeof obj.length !== 'number') {
      return object.keys(obj).length === 0;
    }
    return null;
  }

  /**
   * 等于指定controller的值
   * @param targetname 目标的formcontrolname
   * @returns {(ctrl: formcontrol) => {equalto: {valid: boolean}}}
   */
  static equalto(targetname: string): validatorfn {
    return (control: abstractcontrol): {[key: string]: any} | null => {
      const target = control.root.get(targetname);
      if (target === null) {
        return null;
      }
      if (this.isemptyinputvalue(control.value)) {
        return null;
      }
      return target.value === control.value ? null : {'equalto': { valid: false }};
    };
  }

  /**
   * 反向输入监听指定controller是否与当前值相等
   * @param targetname
   */
  static equalfor(targetname: string): validatorfn {
    return (control: abstractcontrol): {[key: string]: any} | null => {
      const target = control.root.get(targetname);
      if (target === null) {
        return null;
      }
      if (this.isemptyinputvalue(control.value)) {
        return null;
      }
      if (target.value === control.value) {
        const errors = target.errors;
        delete errors['equalto'];

        if (this.isemptyobject(errors)) {
          target.seterrors(null);
        } else {
          target.seterrors(errors);
        }
        return null;
      }
      target.seterrors({ 'equalto': { valid: false } });
    };
  }

  ...
}

(注:)其中g.regex等的是全局变量。

1. 然后formbuilder来实现：

import { component, oninit } from '@angular/core';
import {eventsservice} from '../../../services/events.service';
import {formbuilder, formgroup, validators} from '@angular/forms';
import {g} from '../../../services/data-store.service';
import {fade} from '../../../animations/fade.animation';
import {myvalidators} from '../../../directives/my-validators.directive';

@component({
  selector: 'app-sign-up',
  templateurl: './sign-up.component.html',
  styleurls: ['./sign-up.component.scss'],
  animations: [fade]
})
export class signupcomponent implements oninit {
  signform: formgroup; // 表单组formgroup
  submitting: boolean; // 是否可以提交
  validations = g.validations;

  constructor(private eventsservice: eventsservice, private formbuilder: formbuilder) {
    this.submitting = false;

    // 
    this.init();
  }

  ngoninit() {
    // 设置父组件标题
    this.eventsservice.publish('setsign', { title: '注册', subtitle: { name: '立即登录', uri: '/account/sign-in' } });
  }

  // 立即注册
  onsubmit() {
    console.log(this.signform.getrawvalue());
  }

  // 表单初始化
  private init() {
    this.signform = this.formbuilder.group({
      username: ['', validators.compose([validators.required, validators.maxlength(this.validations.usr_max)])],
      password: ['', validators.compose([
        validators.required,
        validators.minlength(this.validations.pass_min),
        validators.maxlength(this.validations.pass_max),
        myvalidators.equalfor('passwordconfirm')
      ])],
      passwordconfirm: ['', validators.compose([
        validators.required,
        validators.minlength(this.validations.pass_min),
        validators.maxlength(this.validations.pass_max),
        myvalidators.equalto('password')
      ])]
    });
  }
}

(注:)其中fade动画效果。

1. 然后在html模板中，显示表单验证提示信息：

<form [formgroup]="signform" (ngsubmit)="onsubmit()" class="sign-form" @fade>

  <!-- 账号 -->
  <div class="input-group username">
    <span class="addon prev"><i class="civ civ-i-usr"></i></span>
    <input type="text"
      name="username"
      class="form-control form-control-left default"
      placeholder="请输入账号"
      formcontrolname="username"
      autocomplete="off">
    <ul class="errors" *ngif="signform.get('username').invalid && (signform.get('username').dirty || signform.get('username').touched)">
      <li *ngif="signform.get('username').haserror('required')" class="error">
        请输入您的账号!
      </li>
      <li *ngif="signform.get('username').haserror('maxlength')" class="error">
        账号不超过{{ validations.usr_max }}位!
      </li>
    </ul>
  </div> <!-- /.账号 -->
  
  <!-- 密码 -->
  <div class="input-group password">
    <span class="addon prev"><i class="civ civ-i-lock"></i></span>
    <input type="password"
      name="password"
      class="form-control form-control-left default"
      placeholder="请输入密码"
      formcontrolname="password">
    <ul class="errors" *ngif="signform.get('password').invalid && (signform.get('password').dirty || signform.get('password').touched)">
      <li *ngif="signform.get('password').haserror('required')" class="error">
        请输入您的密码!
      </li>
      <li *ngif="signform.get('password').haserror('minlength')" class="error">
        请输入至少{{ validations.pass_min }}位数的密码!
      </li>
      <li *ngif="signform.get('password').haserror('maxlength')" class="error">
        密码不超过{{ validations.pass_max }}位!
      </li>
    </ul>
  </div> <!-- /.密码 -->
  
  <!-- 重复密码 -->
  <div class="input-group password-confirm">
    <span class="addon prev"><i class="civ civ-i-lock"></i></span>
    <input type="password"
           name="passwordconfirm"
           class="form-control form-control-left default"
           placeholder="请再次输入密码"
           formcontrolname="passwordconfirm">
    <ul class="errors" *ngif="signform.get('passwordconfirm').invalid && (signform.get('passwordconfirm').dirty || signform.get('passwordconfirm').touched)">
      <li *ngif="signform.get('passwordconfirm').haserror('required')" class="error">
        请再次输入密码!
      </li>
      <li *ngif="signform.get('passwordconfirm').haserror('minlength')" class="error">
        请输入至少{{ validations.pass_min }}位数的密码!
      </li>
      <li *ngif="signform.get('passwordconfirm').haserror('maxlength')" class="error">
        密码不超过{{ validations.pass_max }}位!
      </li>
      <li *ngif="!signform.get('passwordconfirm').haserror('maxlength') && !signform.get('passwordconfirm').haserror('minlength') && signform.get('passwordconfirm').haserror('equalto')" class="error">
        两次密码输入不一致!
      </li>
    </ul>
  </div> <!-- /.重复密码 -->
  
  <!-- 提交按钮 -->
  <button type="submit"
          class="btn btn-primary btn-block submit"
          [disabled]="submitting || signform.invalid">立即注册</button>
  <!-- /.提交按钮 -->
  
</form>

最后，我们可以看到，实现了想要的效果：

---

(附:)完整的自定义表单验证器：

import {abstractcontrol, formgroup, validatorfn} from '@angular/forms';
import {g} from '../services/data-store.service';

export class myvalidators {
  private static isemptyinputvalue(value) {
    // we don't check for string here so it also works with arrays
    return value == null || value.length === 0;
  }
  private static isemptyobject(obj) {
    if (typeof obj === 'object' && typeof obj.length !== 'number') {
      return object.keys(obj).length === 0;
    }
    return null;
  }

  /**
   * 等于指定controller的值
   * @param targetname 目标的formcontrolname
   * @returns {(ctrl: formcontrol) => {equalto: {valid: boolean}}}
   */
  static equalto(targetname: string): validatorfn {
    return (control: abstractcontrol): {[key: string]: any} | null => {
      const target = control.root.get(targetname);
      if (target === null) {
        return null;
      }
      if (this.isemptyinputvalue(control.value)) {
        return null;
      }
      return target.value === control.value ? null : {'equalto': { valid: false }};
    };
  }

  /**
   * 反向输入监听指定controller是否与当前值相等
   * @param targetname
   */
  static equalfor(targetname: string): validatorfn {
    return (control: abstractcontrol): {[key: string]: any} | null => {
      const target = control.root.get(targetname);
      if (target === null) {
        return null;
      }
      if (this.isemptyinputvalue(control.value)) {
        return null;
      }
      if (target.value === control.value) {
        const errors = target.errors;
        delete errors['equalto'];

        if (this.isemptyobject(errors)) {
          target.seterrors(null);
        } else {
          target.seterrors(errors);
        }
        return null;
      }
      target.seterrors({ 'equalto': { valid: false } });
    };
  }

  /**
   * 验证手机号
   * @returns {(ctrl: formcontrol) => {mobile: {valid: boolean}}}
   */
  static get mobile() {
    return (control: abstractcontrol) => {
      if (this.isemptyinputvalue(control.value)) {
        return null;
      }

      const valid = g.regex.mobile.test(control.value);

      return valid ? null : {
        'mobile': {
          valid: false
        }
      };
    };
  }

  /**
   * 验证身份证
   * @returns {(ctrl: formcontrol) => {idcard: {valid: boolean}}}
   */
  static get idcard() {
    return (control: abstractcontrol) => {
      if (this.isemptyinputvalue(control.value)) {
        return null;
      }

      const valid = g.regex.id_card.test(control.value);

      return valid ? null : {
        'idcard': {
          valid: false
        }
      };
    };
  }

  /**
   * 验证汉字
   * @returns {(ctrl: formcontrol) => {cn: {valid: boolean}}}
   */
  static get cn() {
    return (control: abstractcontrol) => {
      if (this.isemptyinputvalue(control.value)) {
        return null;
      }

      const valid = g.regex.cn.test(control.value);

      return valid ? null : {
        'cn': {
          valid: false
        }
      };
    };
  }

  /**
   * 指定个数数字
   * @param {number} length
   * @returns {(ctrl: formcontrol) => (null | {number: {valid: boolean}})}
   */
  static number(length: number = 6) {
    return (control: abstractcontrol) => {
      if (this.isemptyinputvalue(control.value)) {
        return null;
      }

      const valid = new regexp(`^\\d{${length}}$`).test(control.value);

      return valid ? null : {
        'number': {
          valid: false
        }
      };
    };
  }

  /**
   * 强密码（必须包含数字字母）
   * @returns {(ctrl: formcontrol) => (null | {number: {valid: boolean}})}
   */
  static get strictpass() {
    return (control: abstractcontrol) => {
      if (this.isemptyinputvalue(control.value)) {
        return null;
      }

      const valid = g.regex.strict_pass.test(control.value);

      return valid ? null : {
        'strictpass': {
          valid: false
        }
      };
    };
  }
}