Validation rules in React Form validator component

16 Mar 202324 minutes to read

Default Rules

The FormValidator has following default validation rules, which are used to validate the form.

Rules Description Example
required The form input element must have any input values a or 1 or -
email The form input element must have valid email format values form@syncfusion.com
url The form input element must have valid url format values http://syncfusion.com/
date The form input element must have valid date format values 05/15/2017
dateIso The form input element must have valid dateISO format values 2017-05-15
number The form input element must have valid number format values 1.0 or 1
digits The form input element must have valid digits values 1
maxLength Input value must have less than or equal to maxLength character length if maxLength: 5, check is valid and checking is invalid
minLength Input value must have greater than or equal to minLength character length if minLength: 5, testing is valid and test is invalid
rangeLength Input value must have value between rangeLength character length if rangeLength: [4,5], test is valid and key is invalid
range Input value must have value between range number if range: [4,5], 4 is valid and 6 is invalid
max Input value must have less than or equal to max number if max: 3, 3 is valid and 4 is invalid
min Input value must have greater than or equal to min number if min: 4, 5 is valid and 2 is invalid
regex Input value must have valid regex format if regex: '^[A-z]+$', a is valid and 1 is invalid

The rules option should map the input element’s name attribute.
The FormValidator library only validates the mapped input elements.

Defining Custom Rules

You can also define custom rules in the rules property and validate the form with custom logics.

The custom validation method need to return the boolean value for validating an input.

import { FormValidator } from '@syncfusion/ej2-inputs';
import { DialogComponent } from '@syncfusion/ej2-react-popups';
import * as React from 'react';
import * as ReactDOM from 'react-dom';
export default class Validation extends React.Component {
    dialogInstance;
    formObject;
    animationSettings = { effect: 'Zoom' };
    floatFocus(args) {
        args.target.parentElement.classList.add('e-input-focus');
    }
    floatBlur(args) {
        args.target.parentElement.classList.remove('e-input-focus');
    }
    // Dialog will be closed, while clicking on overlay
    onOverlayClick() {
        this.dialogInstance.hide();
    }
    componentDidMount() {
        const options = {
            // add the rules for validation
            rules: {
                'email': {
                    required: [true, '* Enter your email']
                },
                'mobile': {
                    required: [true, '* Enter your mobile number']
                },
                'name': {
                    required: [true, '* Enter your name']
                },
            }
        };
        // initialize the form validator
        this.formObject = new FormValidator('#form1', options);
    }
    onSubmitClick() {
        if (this.formObject.validate()) {
            this.formObject.element.reset();
            this.dialogInstance.show();
        }
    }
    render() {
        return (<div className='control-pane'>
    <div className='control-section col-lg-12'>
      <h4 className="form-title">Validation Support</h4>
      <div className='validation_wrapper'>
        <div className="control_wrapper" id="control_wrapper">
          <form id="form1" method="post">
            <div className="form-group">
              <div className="e-float-input">
                <input type="text" id="name" name="name" onFocus={this.floatFocus} onBlur={this.floatBlur} data-msg-containerid="nameError"/>
                <span className="e-float-line"/>
                <label className="e-float-text e-label-top" htmlFor="name">Name</label>
              </div>
              <div id="nameError"/>
            </div>
            <div className="form-group">
              <div className="e-float-input">
                <input type="email" id="Email" name="email" data-msg-containerid="mailError"/>
                <span className="e-float-line"/>
                <label className="e-float-text e-label-top" htmlFor="email">Email</label>
              </div>
              <div id="mailError"/>
            </div>
            <div className="form-group">
              <div className="e-float-input">
                <input type="text" id="mobileno" name="mobile" data-msg-containerid="noError"/>
                <span className="e-float-line"/>
                <label className="e-float-text e-label-top" htmlFor="mobile">Mobile no</label>
              </div>
              <div id="noError"/>
            </div>
          </form>
          <br />
          <br />
          <div className="submitBtn">
            <button className="submit-btn e-btn" onClick={this.onSubmitClick = this.onSubmitClick.bind(this)} id="submit-btn">Submit</button>
          </div>
          <div id="confirmationDialog"/> </div>
        </div>
      </div>
      <DialogComponent id="defaultdialog" isModal={true} visible={false} content='Your details has been updated successfully, Thank you' animationSettings={this.animationSettings} width={'50%'} ref={dialog => this.dialogInstance = dialog} target={'.control-section'} overlayClick={this.onOverlayClick = this.onOverlayClick.bind(this)}/>
    </div>);
    }
}
ReactDOM.render(<Validation />, document.getElementById('validation'));
import { select } from '@syncfusion/ej2-base';
import { FormValidator, FormValidatorModel } from '@syncfusion/ej2-inputs';
import { DialogComponent } from '@syncfusion/ej2-react-popups';
import * as React from 'react';
import * as ReactDOM from 'react-dom';

export default class Validation extends React.Component<{}, {}> {
public dialogInstance: DialogComponent;
public formObject: FormValidator;
private animationSettings: object = { effect: 'Zoom' };
public floatFocus(args: any): void {
  args.target.parentElement.classList.add('e-input-focus');
}
public floatBlur(args: any): void {
  args.target.parentElement.classList.remove('e-input-focus');
}
  // Dialog will be closed, while clicking on overlay
  public onOverlayClick() {
        this.dialogInstance.hide();
  }
  public componentDidMount(): void {
        const options: FormValidatorModel = {
          // add the rules for validation
         rules: {
          'email': {
            required: [true, '* Enter your email']
          },
          'mobile': {
            required: [true, '* Enter your mobile number']
          },
          'name': {
              required: [true, '* Enter your name']
          },
        }
      };
      // initialize the form validator
      this.formObject = new FormValidator('#form1', options);
  }

  public onSubmitClick(): void {
  if(this.formObject.validate()) {
    this.formObject.element.reset();
    this.dialogInstance.show();
      }
  }

public render(): JSX.Element {
  return (    <div className = 'control-pane'>
    <div className='control-section col-lg-12'>
      <h4 className="form-title">Validation Support</h4>
      <div className='validation_wrapper'>
        <div className="control_wrapper" id="control_wrapper">
          <form id="form1"  method="post">
            <div className="form-group" >
              <div className="e-float-input">
                <input type="text" id="name" name="name" onFocus= {this.floatFocus} onBlur= {this.floatBlur}  data-msg-containerid="nameError" />
                <span className="e-float-line"/>
                <label className="e-float-text e-label-top" htmlFor="name">Name</label>
              </div>
              <div id="nameError"/>
            </div>
            <div className="form-group">
              <div className="e-float-input">
                <input type="email" id="Email" name="email" data-msg-containerid="mailError"/>
                <span className="e-float-line"/>
                <label className="e-float-text e-label-top" htmlFor="email" >Email</label>
              </div>
              <div id="mailError"/>
            </div>
            <div className="form-group" >
              <div className="e-float-input">
                <input type="text" id="mobileno" name="mobile" data-msg-containerid="noError" />
                <span className="e-float-line"/>
                <label className="e-float-text e-label-top"  htmlFor="mobile" >Mobile no</label>
              </div>
              <div id="noError"/>
            </div>
          </form>
          <br/>
          <br/>
          <div className="submitBtn">
            <button className="submit-btn e-btn" onClick={this.onSubmitClick = this.onSubmitClick.bind(this)} id="submit-btn">Submit</button>
          </div>
          <div id="confirmationDialog"/> </div>
        </div>
      </div>
      <DialogComponent id="defaultdialog" isModal={true} visible ={false} content = 'Your details has been updated successfully, Thank you' animationSettings={this.animationSettings} width={'50%'}  ref={dialog => this.dialogInstance = dialog!}
      target={'.control-section'} overlayClick={this.onOverlayClick=this.onOverlayClick.bind(this)} />
    </div>) }
}

ReactDOM.render(<Validation />, document.getElementById('validation'));

Adding or Removing Rules

After creating FormValidator object, you can add more rules to an input element by using addRules method and you can also remove an existing rule from the input element by using removeRules method.

import { FormValidator, FormValidatorModel } from '@syncfusion/ej2-inputs';
import * as React from 'react';

export default class Validation extends React.Component<{}, {}> {
public formObject: FormValidator;

public componentDidMount(): void {
        const options: FormValidatorModel = {
         rules: {
          'email': {
            required: [true, '* Enter your email']
          },
          'mobile': {
            required: [true, '* Enter your mobile number']
          },
          'name': {
              required: [true, '* Enter your name']
          },
        }
      };
      this.formObject = new FormValidator('#form1', options);
      // Add email rule to user element
      this.formObject.addRules('name', { maxLength : [5, 'Character count should not greater than 5'] });
      // Remove number rule from age element
      this.formObject.removeRules('mobile', ['number']);
  }

  public render() {
    return (
      <form id='form1'>
        <div>
          <input type='text' className='e-input' name='email'/>
        </div>
        <div>
          <input type='text' className='e-input' name='name'/>
        </div>
        <div>
          <input type='text' className='e-input' name='mobile'/>
        </div>
      </form>
    )
  }
}

Validating a single Element

The validate method have an optional argument, where you can pass an input element’s name attribute to validate its value against the defined rule.

import { FormValidator, FormValidatorModel } from '@syncfusion/ej2-inputs';
import * as React from 'react';

export default class Validation extends React.Component<{}, {}> {
public formObject: FormValidator;

public componentDidMount(): void {
        const options: FormValidatorModel = {
         rules: {
          'email': {
            required: [true, '* Enter your email']
          },
          'mobile': {
            required: [true, '* Enter your mobile number']
          },
          'name': {
              required: [true, '* Enter your name']
          },
        }
      };
      this.formObject = new FormValidator('#form1', options);
      // Add email rule to user element
      this.formObject.validate('name');
  }

  public render() {
    return (
      <form id='form1'>
        <div>
          <input type='text' className='e-input' name='email'/>
        </div>
        <div>
          <input type='text' className='e-input' name='name'/>
        </div>
        <div>
          <input type='text' className='e-input' name='mobile'/>
        </div>
      </form>
    )
  }

}