AUR4103

Error Message

AUR4103: Serializing a non-string displayName for rule property is not supported. Given: {{value}}

Description

This error occurs when validation rule serialization encounters a displayName value that is not a string. Only string displayName values are supported for serialization.

Common Scenarios

import { ValidationRules } from '@aurelia/validation';

class Model {
  public name = '';
}

// ❌ Non-string displayName
ValidationRules
  .ensure((x: Model) => x.name)
  .displayName({ text: 'Name' } as any)
  .required()
  .on(Model);

Solution

• Ensure displayName is a string when rules need to be serialized.

import { ValidationRules } from '@aurelia/validation';

class Model {
  public name = '';
}

// ✅ String displayName
ValidationRules
  .ensure((x: Model) => x.name)
  .displayName('Name')
  .required()
  .on(Model);

Troubleshooting

• If you rely on dynamic/localized display names, apply them at runtime (after hydration) rather than serializing them.

• Inspect the error’s {{value}} to find which rule property had an unsupported displayName.