AUR0756

Error Message

AUR0756: Cannot resolve ViewFactory without a (valid) name.

Description

This internal error occurs when Aurelia's rendering engine attempts to retrieve a ViewFactory (used to create view instances) but lacks a valid identifier for the component whose ViewFactory is needed. The identifier is typically the component's definition object or its registered resource name.

Cause

Similar to AUR0755, this error is generally not caused directly by standard application code. It points to an issue within the rendering pipeline or resource management. Possible scenarios include:

1. Corrupted Component Definition: A component's definition might be missing, incomplete, or corrupted internally before the ViewFactory is requested. This could potentially happen due to complex interactions or bugs.

2. Incorrect Dynamic Composition: Issues in how components are dynamically composed (e.g., using <au-compose>) might lead to situations where a component's definition is not correctly passed or resolved. For example, providing null, undefined, or an invalid value to the component bindable of <au-compose>.

3. Manual Internal API Use: Improper interaction with internal Aurelia APIs related to resource resolution or rendering could lead to this state.

4. Potential Bug in Aurelia: This could indicate an underlying bug in how Aurelia handles component definitions or resolves resources internally.

Solution

Focus on standard practices and identifying the source of the invalid definition:

1. Check Dynamic Composition: If using <au-compose>, ensure the value bound to the component attribute is always a valid component definition (the imported class), its registered name (string), or a Promise resolving to one. Avoid passing null, undefined, or other invalid types. Add checks or defaults if necessary.

   <!-- Ensure 'myDynamicComponent' resolves to a valid component or name -->
   <au-compose component.bind="myDynamicComponent || DefaultComponent"></au-compose>

2. Verify Component Definitions: Ensure all custom elements and attributes are correctly defined with @customElement or @customAttribute decorators and have valid names.

3. Avoid Internal API Manipulation: Stick to public, documented Aurelia APIs.

4. Update Aurelia Packages: Keep Aurelia packages updated to benefit from bug fixes.

5. Isolate and Reproduce: Try to find the specific scenario or component causing the error. Create a minimal reproduction case. This helps determine if it's related to specific application logic (like dynamic composition) or a framework issue.

6. Report the Issue: If a framework bug is suspected, report it with a clear reproduction on the Aurelia GitHub repository.

Debugging Tips

• Examine the call stack in the debugger when the error occurs to see the context in which getViewFactory was called without a valid name/definition.

• If using <au-compose>, log the value being passed to the component attribute just before it's used.

• Simplify the template and view model of the suspected component to isolate the part triggering the error.