João Eirinha developed a targeted linting enhancement for the facebook/react repository, focusing on enforcing correct usage of the useEffectEvent hook. He implemented a new ESLint rule in JavaScript and TypeScript that disallows passing useEffectEvent directly as a JSX prop, addressing a common source of misuse in React applications. The solution included comprehensive test coverage and improved error messaging to guide developers toward best practices. By concentrating on code quality and frontend development, João’s work reduced the risk of runtime errors and improved the overall reliability of React hook usage, delivering measurable improvements to developer experience and project maintainability.