Class Validator

    Novu requires the `class-validator-jsonschema` package to generate JSON schemas from your DTOs. You may also need the `reflect-metadata` package.
</Step>
<Step title="Use Class Validator in your workflow">
    After installation, the Class Validator DTOs can be used interchangeably with the `controlSchema` and `payloadSchema` options in your workflow definitions.

    ```tsx

    
    class TestComponent {
        @IsString()
        subject: string;
  
        @IsString()
        content: string;
    }
    
    class TestControlSchema {
        @IsBoolean()
        hideBanner: boolean;
  
        @IsString()
        @IsNotEmpty()
        @IsOptional()
        subject?: string;
  
        // Allowing no code control over the component in the Dashboard UI
        @Type(() => NewSignUpComponent)
        @NestedValidation({ each: true })
        @IsOptional()
        components?: NewSignUpComponent[];
    }
    
    class TestPayloadSchema {
        @IsString()
        username: string;
    }

    export const testWorkflow = workflow('test-workflow', async ({ step, payload }) => {
        await step.email('send-email', async (controls) => {
            return {
                subject: controls.subject,
                body: 'Hello, World!',
            };
        },
        {
            controlSchema: TestControlSchema,
        });
    }, {
        payloadSchema: TestPayloadSchema,
    });
    ```
</Step>