TypeScript was actually an inspiration - and jsig draws heavily on TypeScript's inspirations (especially ES6, Go, and to some extent [particularly generics], C#

TypeScript was actually an inspiration - and jsig draws heavily on TypeScript's inspirations (especially ES6, Go, and to some extent [particularly generics], C#). However TypeScript was optimized for building tooling. It also requires changing the actual executable code you write and investing in a workflow around the TypeScript compiler. With jsig, you just write a comment. My experience working almost exclusively in Node.js for the past year as shown me that plain JavaScript and minimal IDE support is sufficient if you embrace a philosophy of small, self-contained, loosely-coupled modules, each with their own tests and documentation. Writing this documentation in a clear way has been a pain point for me, however. jsig grew out of some of the conventions we've been using on my team to address the ad hoc or underspecified documentation we've dealt with. With TypeScript, it's possible to write just in JavaScript and keep your TypeScript declarations in an external file (see, for example, [TSD](https://github.com/Diullei/tsd) https://github.com/Diullei/tsd)) - but this is impractical. Plus, TypeScript does not support generic types, which are especially convenient for things like Callback<Buffer> or Promise<Buffer>.