Declare process var in global declare typescript .d.ts

Issue

I know for setting .env types, we write this code in .d.ts:

  var process: {
   env: {
      MONGO_DB_URL: string;
    }
  }

But if I do this in global declaration, like this:

declare global {
  var process: {
   env: {
      MONGO_DB_URL: string;
    }
  }
  module Express {
    export interface Request {
      decodedToken: DecodedToken;
    }
    export interface Application {
      io: Server;
      sessionQIDtoSocketMap: Record<string, string>;
    }
  }
}

It gives me this error:

var process: globalThis.NodeJS.Process
Subsequent variable declarations must have the same type.  Variable 'process' must be of type 'Process', but here has type '{ env: { MONGO_DB_URL: string; }; }'.ts(2403)
globals.d.ts(44, 13): 'process' was also declared here.

If I do something like this:

declare var process: {
  env: {
    MONGO_DB_URL: string;
  };
};
declare global {
  module Express {
    export interface Request {
      decodedToken: DecodedToken;
    }
    export interface Application {
      io: Server;
      sessionQIDtoSocketMap: Record<string, string>;
    }
  }
}

The errors then go away but typescript still doesn't register the types

Solution

I had the same issue a while back. Referencing my .env variables like this solved the problem for me

const MONGODB_URL = process.env["MONGO_DB_URL"];

EDIT

This is what I ended up doing in the end, it's slightly better than my previous answer. In globals.d.ts:

declare namespace NodeJS {
  interface ProcessEnv {
   MONGO_DB_URL: string
   //etc...
  }
}

Then just reference .env variables same as before using dot notation. You should get intellisense

When there is declare global, then the code should be:

declare global {
  namespace NodeJS {
    export interface ProcessEnv {
      JWT_SECRET: string;
    }
  }
}

Answered By - bkw1491