A JavaScript (Object Oriented) developer designs, tests, and implements web applications using JavaScript language following Object-Oriented principles. They leverage JavaScript frameworks like Vue.js, AngularJS, or React.js to create user-friendly interfaces. They structure code using classes, objects, and inheritance for improved readability and reusability. They debug and fix issues, optimize code for performance, and ensure cross-platform compatibility. They often collaborate with other developers or teams, contribute to code reviews, and may also interact with clients to understand requirements. They stay updated with new JavaScript features and best practices, ensuring secure, efficient, and maintainable code.