Cucumber JVM ↔ Cucumber for JavaScript: Can Shared Gherkin Feature Files Use Custom Parameter Types?

Direct Resolution

No, shared Gherkin feature files cannot automatically utilize custom parameter types consistently across Cucumber JVM and Cucumber for JavaScript.

The Gherkin syntax itself is portable; however, the mechanism for defining, parsing, and converting custom parameter types is entirely implemented within the specific runtime environment (Java for JVM, JavaScript for JS).

Likely Explanation vs. Confirmed Facts

Likely Explanation: Some developers might assume that if the Gherkin syntax is the same, the type resolution logic could be abstracted. This is incorrect because the underlying expression parsing engines and type conversion logic are native to each language ecosystem.

Confirmed Facts

• Cucumber Expressions for built-in types show high portability.
• Custom parameter type implementation is runtime-specific, not inherently portable.
• A single, shared expression factory consumable by both runtimes is not a standard, supported feature.

Necessary Steps for This Case

1. Define the required custom type logic (e.g., a specific data structure) in Cucumber JVM using its type conversion mechanisms.
2. Implement the functionally equivalent custom type logic in Cucumber for JavaScript using its corresponding type definition methods.
3. Ensure both test suites execute the identical Gherkin feature file against their respective, language-specific step definitions.

Diagnostic Detail Request

To refine this advice, please specify the exact nature of the custom parameter type (e.g., a specific class, a complex JSON structure, or a custom domain object).