It makes the types available in runtime. You can take a look at the current WIP version of the new upcoming Deepkit book which explains it in great detail: https://deepkit-book.herokuapp.com See section "2. Runtime Types"

Thanks – the question I had was answered in the "Bytecode" part of that section: https://deepkit-book.herokuapp.com/deepkit-book-english.html...

My summary is that the DeepKit compiler is a JS transpiler (used as a ts-node or webpack plugin, or conveniently/invasively as a replacement of node_modules/typescript) that produces code like this:

    //TypeScript
    export type TypeA = string[];

    //generated JavaScript
    export const __ΩtypeA = ['&F'];

    //TypeScript
    function log(message: string): void {}

    //generated JavaScript
    function log(message) {}
    log.__type = ['message', 'log', 'P&2!$/"'];

Where '&F' and 'P&2!$/"' are the compact bytecode translations of the types ("&" means string, "F" means array) and '__Ω' is a prefix used to avoid naming conflicts.

Personally, I'd love to see a live example of code in & compiled code out on the homepage. I'm sure it's on your roadmap :)