RFLCT: Bringing Runtime Type Metadata to TypeScript 7

If you've built large-scale applications in TypeScript, chances are you've used a Dependency Injection (DI) container. As the creator of InversifyJS, I've spent years thinking deeply about inversion of control, decoupling, and how to make enterprise patterns feel natural in TypeScript. But for all those years, there has been a glaring elephant in the room: our heavy reliance on experimentalDecorators and emitDecoratorMetadata . These compiler flags have served us well, but they are exactly that— experimental . They tie us to legacy decorator implementations, require specific compiler configurations, and often feel like a magic black box that doesn't perfectly align with modern build pipelines. I've spent a lot of time recently thinking about how we could finally drop these flags entirely while keeping the developer experience pristine. With the release of TypeScript 7, I'm thrilled to introduce the solution: 🪞 RFLCT . What is RFLCT? RFLCT is an ahead-of-time (AOT) reflect metadata injector for TypeScript 7. It injects design:symbols and design:arguments directly at build time. Zero decorators. Zero emitDecoratorMetadata . It integrates seamlessly with virtually any build tool (Vite, Rollup, webpack, esbuild) via unplugin , or you can use the built-in CLI using the TypeScript 7 API for standalone tsgo projects. Let's look at how it actually feels to write code with RFLCT. The Magic: Before and After With RFLCT, you annotate the types you want to expose to your runtime metadata using a special Reflect<T> wrapper type. What you write: import { Reflect , resolve } from " rflct " ; interface Shape { sides : number ; } class Polygon { constructor ( public shape : Reflect < Shape > , public label : Reflect < string , { optional : true } > ) {} } // resolve<T>() → the runtime identity of T (Symbol for interfaces, class for classes) container . bind ( resolve < Shape > ()). to ( Polygon ); What RFLCT compiles it to: Notice how the interfaces are safely converted into global