Diagnostic codes: must-export: A file in a `mustExport` rule exports no name that matches the rule's name pattern. # must-export > A file in a `mustExport` rule exports no name that matches the rule's name pattern. Rule violations. This text is what `archangel docs must-export` prints. A file in a `mustExport` rule exports no name that matches the rule’s name pattern. ## Example ```ts // rule({ files: '**/*.view.tsx', mustExport: '{FileName}' }) // src/button.view.tsx, which exports only ButtonView, not Button ``` ## What to do Export the name the message gives. A re-export counts, and so does every name an `export *` chain brings in, except `default`, which `export *` never passes on.