AUR0221

Error Message

AUR0221: Trying to assign value to readonly property "{{property}}" through computed observer.

Where {{property}} is the readonly property name.

Description

This error occurs when Aurelia tries to assign a value to a readonly property via a computed observer. Readonly properties (for example getters without setters) cannot be written to.

Common Scenarios

• Two-way binding to a getter-only property.

• Binding a writable target to a computed/read-only source.

Solution

• Bind to writable properties for two-way scenarios.

• If you need a computed-like value that is also assignable, implement a setter or use a separate backing field.