Explore the powerful metaprogramming capabilities of ES6 Proxy in this JSConf Budapest 2017 talk by Eirik Vullum. Dive into the world of JavaScript metaprogramming, learning how to create custom syntax, define new operators, and leverage introspection, self-modification, and intercession techniques. Discover the core concepts of Proxies in JavaScript, including targets, handlers, and traps. Gain insights into practical applications such as instrumentation and creating observable objects. Compare naive and Proxy approaches to solving common problems. Uncover unconventional uses like redefining undefined and implementing "seatbelts" for JavaScript. Whether you're a seasoned developer or new to metaprogramming, this 26-minute presentation offers valuable knowledge on harnessing the full potential of ES6 Proxy in modern browsers and Node.js environments.