JavaScript Developer for Web App

I'm looking for a skilled JavaScript developer to assist in building a web application. While specific functionalities and frameworks haven't been decided yet, the ideal candidate should have a deep understanding of JavaScript and its ecosystem, with extensive experience in developing web applications.

Key Skills and Experience:
- Proficient in JavaScript
- Extensive experience with web application development
- Knowledge of best practices for front-end development
- Familiar with responsive design principles
- Experience with debugging and troubleshooting
- Capability to work collaboratively in a team