React Validator - CompareRule

A validation rule that demands that a validated editor has a value that is equal to a specified expression.

import { ValidationRulesTypes } from "devextreme-react/validation-rules"
Type: ValidationRulesTypes.CompareRule

To specify the expression that the validated field must match, set the rule's comparisonTarget configuration property. Assign a function to this property. The validated value will be compared to the function's return value. The comparison will be performed by using the operator that is set for the comparisonType property.

View Demo

See Also

comparisonTarget

Specifies the function whose return value is used for comparison with the validated value.

Type:

Function

Return Value:

Object

A value to be compared with the validated value.

The rule is valid if the comparison between the validated value and the return value of the comparisonTarget function evaluates to true. The operator specified by the comparisonType property is used to compare values.

comparisonType

Specifies the operator to be used for comparing the validated value with the target.

Type:

String

Default Value: '=='
Accepted Values: '!=' | '!==' | '<' | '<=' | '==' | '===' | '>' | '>='

ignoreEmptyValue

If set to true, empty values are valid.

Type:

Boolean

Default Value: false

message

Specifies the message that is shown if the rule is broken.

Type:

String

Default Value: 'Values do not match'

An error message can be specified as follows:

  • Hard-code the message

    jQuery
    index.js
    $(function() {
    $("#textBox").dxTextBox({ ... })
        .dxValidator({
            type: "compare",
            message: "My custom message"
        });
});
    Angular
    app.component.html
    app.module.ts
    <dx-text-box> 
    <dx-validator>
        <dxi-validation-rule 
            type="compare" 
            message="My custom message">
        </dxi-validation-rule>
    </dx-validator>
</dx-text-box>
    import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppComponent } from './app.component';

import { DxValidatorModule,
         DxTextBoxModule } from 'devextreme-angular';

@NgModule({
    declarations: [
        AppComponent
    ],
    imports: [
        DxTextBoxModule,
        BrowserModule,
        DxValidatorModule
    ],
    providers: [],
    bootstrap: [AppComponent]
})
export class AppModule { }
    Vue
    App.vue
    <template>
    <DxTextBox>
        <DxValidator>
            <DxCompareRule
                message="My custom message"
            />
        </DxValidator>
    </DxTextBox>
</template>

<script>
import 'devextreme/dist/css/dx.light.css';

import { DxTextBox } from 'devextreme-vue/text-box';
import {
    DxValidator,
    DxCompareRule
} from 'devextreme-vue/validator';

export default {
    components: {
        DxTextBox,
        DxValidator,
        DxCompareRule
    }
}
</script>
    React
    App.js
    import React from 'react';

import 'devextreme/dist/css/dx.light.css';

import { TextBox } from 'devextreme-react/text-box';
import {
    Validator,
    CompareRule
} from 'devextreme-react/validator';

class App extends React.Component {
    render() {
        return (
            <TextBox>
                <Validator>
                    <CompareRule
                        message="My custom message" />
                </Validator>
            </TextBox>
        );
    }
}
export default App;

  • Hide the message

    jQuery
    index.js
    $(function() {
    $("#textBox").dxTextBox({ ... })
        .dxValidator({
            type: "compare",
            message: ""
        });
});
    Angular
    app.component.html
    app.module.ts
    <dx-text-box>
    <dx-validator>
        <dxi-validation-rule 
            type="compare" 
            message="">
        </dxi-validation-rule>
    </dx-validator>
</dx-text-box>
    import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppComponent } from './app.component';

 import { DxValidatorModule,
          DxTextBoxModule } from 'devextreme-angular';

@NgModule({
    declarations: [
        AppComponent
    ],
    imports: [
        BrowserModule,
        DxValidatorModule,
        DxTextBoxModule
    ],
    providers: [],
    bootstrap: [AppComponent]
})
export class AppModule { }
    Vue
    App.vue
    <template>
    <DxTextBox>
        <DxValidator>
            <DxCompareRule
                message=""
            />
        </DxValidator>
    </DxTextBox>
</template>

<script>
import 'devextreme/dist/css/dx.light.css';

import { DxTextBox } from 'devextreme-vue/text-box';
import {
    DxValidator,
    DxCompareRule
} from 'devextreme-vue/validator';

export default {
    components: {
        DxTextBox,
        DxValidator,
        DxCompareRule
    }
}
</script>
    React
    App.js
    import React from 'react';

import 'devextreme/dist/css/dx.light.css';

import { TextBox } from 'devextreme-react/text-box';
import {
    Validator,
    CompareRule
} from 'devextreme-react/validator';

class App extends React.Component {
    render() {
        return (
            <TextBox>
                <Validator>
                    <CompareRule
                        message="" />
                </Validator>
            </TextBox>
        );
    }
}
export default App;

  • Display the editor's name in the message

    jQuery
    index.js
    $(function() {
    $("#textBox").dxTextBox({ ... })
        .dxValidator({
            name: "Passwords", // The error message will be "Passwords do not match"
            validationRules: [{
                type: "compare"
            }]
        });
});
    Angular
    app.component.html
    app.module.ts
    <dx-text-box>
    <!-- The error message will be "Passwords do not match" -->
    <dx-validator name="Passwords">
        <dxi-validation-rule 
            type="compare">
        </dxi-validation-rule>
    </dx-validator>
</dx-text-box>
    import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppComponent } from './app.component';

import { DxValidatorModule,
         DxTextBoxModule } from 'devextreme-angular';

@NgModule({
    declarations: [
        AppComponent
    ],
    imports: [
        BrowserModule,
        DxValidatorModule,
        DxTextBoxModule
    ],
    providers: [],
    bootstrap: [AppComponent]
})
export class AppModule { }
    Vue
    App.vue
    <template>
    <DxTextBox>
        <!-- The error message will be "Passwords do not match" -->
        <DxValidator name="Passwords">
            <DxCompareRule />
        </DxValidator>
    </DxTextBox>
</template>

<script>
import 'devextreme/dist/css/dx.light.css';

import { DxTextBox } from 'devextreme-vue/text-box';
import {
    DxValidator,
    DxCompareRule
} from 'devextreme-vue/validator';

export default {
    components: {
        DxValidator,
        DxCompareRule
    }
}
</script>
    React
    App.js
    import React from 'react';

import 'devextreme/dist/css/dx.light.css';

import { TextBox } from 'devextreme-react/text-box';
import {
    Validator,
    CompareRule
} from 'devextreme-react/validator';

class App extends React.Component {
    render() {
        return (
            <TextBox>
                {/* The error message will be "Passwords do not match" */}
                <Validator name="Passwords">
                    <CompareRule} />
                </Validator>
            </TextBox>
        );
    }
}

export default App;

type

Specifies the rule type. Set it to "compare" to use the CompareRule.

Type:

String

Accepted Values: 'required' | 'numeric' | 'range' | 'stringLength' | 'custom' | 'compare' | 'pattern' | 'email' | 'async'