AUR4102

Error Message

AUR4102: Unable to parse accessor function:
<function source>

Description

This error occurs when the validation serializer/deserializer tries to parse an accessor function (for example (x) => x.someProp) but cannot extract a supported property access from it.

Common Scenarios

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

// ❌ Unsupported accessor shape for serialization
ValidationRules
  .ensure((x: any) => x[getDynamicKey()])
  .required()
  .on(class Model {});

Solution

• Use a simple property accessor that the validation system can interpret.

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

class Model {
  public name = '';
}

// ✅ Simple accessor
ValidationRules
  .ensure((x: Model) => x.name)
  .required()
  .on(Model);

Troubleshooting

• Keep accessors to direct property access (x => x.prop) when you intend to serialize rules.

• If you need dynamic behavior, avoid serialization or build rules at runtime instead of hydrating from serialized data.