  This paper investigates the integration and assessment of IntelliGame, a
gamification plugin initially designed for Java development, within the realm
of JavaScript unit testing. We aim to verify the generalizability of
IntelliGame to JavaScript development and to provide valuable insights into the
experiment's design. For this, we first customize IntelliGame for JavaScript,
and then conduct a controlled experiment involving 152 participants utilizing
the Jest testing framework, and finally examine its influence on testing
behavior and the overall developer experience. The findings from this study
provide valuable insights for improving JavaScript testing methodologies
through the incorporation of gamification.
