Unable to extend Express Request in TypeScript

I've had the same issue...

Can't you just use an extended request? like:

interface RequestWithUser extends Request {
    user?: User;
}
router.post('something',(req: RequestWithUser, res: Response, next)=>{
   const user = req.user;
   ...
}

On another note, if you're using async callbacks with express make sure to user express-async wrappers or make sure you know exactly what you're doing. I recommend: awaitjs

The problem is that you are not augmenting the Express global namespace defined by express you are creating a new namespace in your module (the file becomes a module once you use an import).

The solution is to declare the namespace in global

import { User } from "./src/models/user";

declare global {
    namespace Express {
        export interface Request {
            user: User;
        }
    }
}

Or not use the module import syntax, just reference the type:

declare namespace Express {
    export interface Request {
        user: import("./src/models/user").User;
    }
}