Can't extend express Request type

[brunolm]

I've tried this, this, etc

// ./typings/express/index.d.ts
declare namespace Express {
  export interface Request {
     token?: string
  }
}

Example usage:

import * as express from 'express'

(req: express.Request, res: express.Response, next: express.NextFunction) => {

  const foo = req.token

}

It does work if I compile directly (tsc -p .), it does work in Visual Code, but when I try to run with ts-node I always get:

error TS2339: Property 'token' does not exist on type 'Request'.

Any idea how can I make it work with ts-node?

Versions: ts-node@7.0.1 typescript@3.0.1

https://stackoverflow.com/q/53765895/340760

[blakeembrey]

What’s your tsconfig.json?

[brunolm]

{
  "compilerOptions": {
    "module": "commonjs",
    "target": "es6",
    "noImplicitAny": false,
    "sourceMap": true,
    "outDir": "dist",
    "experimentalDecorators": true,
    "esModuleInterop": true
  },
  "exclude": ["node_modules"]
}

I also tried with "typeRoots": ["./node_modules/@types", "./typings"]

[blakeembrey]

@brunolm That wouldn't work because it'd just discover the first one, not all of them. You can always use the /// <reference /> directive to resolve the one you specifically want to extend (and put your typeRoots first, otherwise you're just resolving @types anyway - it may even work by just switching the order of typeRoots above and no need for reference since one is a module and the other definition is global).

[blakeembrey]

Oh, also, you probably should just put your overrides in a different folder and it would be a non-issue. The problem is the conflict between two Express packages being resolved, but you can create a different package named something to do with your app or anything else that doesn’t conflict.

[3mard]

As this is confusing a lot of people to get right, I'd suggest setting up a working example in the docs

[brunolm]

I don't fully understand why that's required now. I can confirm that this worked before:

versions

"typescript": "2.3.4",
"ts-node": "3.0.4",

tsconfig.json

{
  "compilerOptions": {
    "module": "commonjs",
    "target": "es6",
    "noImplicitAny": false,
    "sourceMap": true
  }
}

typings/foo.d.ts

declare module Express {
  export interface Request {
    knex: any;
    config: any;
    client: { id: number; name: string; };
  }
}

[blakeembrey]

Please see the README and CHANGELOG, and possibly search past issues to find why it was changed.

[blakeembrey]

There is also an example in the README for adding custom types and modules. If you’d like to expand upon it, please feel free to submit a PR!

[blakeembrey]

Just checked and we should invert the resolution order of types so it works as expected here.

Edit: The reason for the change is also in the README.

[henrikra]

With --files in ts-node command local declaration files are recognized. Example command: ts-node --files src/index.ts

Can you guys @3mard @blakeembrey tell WHY this works? I would like understand more :) Also is this the best solution for this problem or is it only a workaround?

[brunolm]

I gave up and started to do this:

req['token'] = 'foo'

And then casting to something when needed.

[3mard]

@henrikra I think this is a design decision that was made to optimize ts-node (why include .d.ts files that your app are not using anyway ?)

https://github.com/TypeStrong/ts-node/blob/master/src/index.ts#L481

[3mard]

@brunolm @henrikra I created this repo example https://github.com/3mard/ts-node-example for extending express request

[saoudrizwan]

Thanks to this comment by @blakeembrey, I got my declaration merges working! All you need to do is put "./typings" before "./node_modules/@types".

"typeRoots": ["./typings", "./node_modules/@types"]

[vschoener]

@saoudrizwan Thanks it works :)

[marcosfede]

This worked for me:

• create express.d.ts file in typings folder with contents

declare module 'express-serve-static-core' {
  interface Request {
    foo?: string
  }
}

[brunolm]

@marcosfede your code makes everything be an any

If I delete your file the types work again.

[marcellsimon]

Thanks to this comment by @blakeembrey, I got my declaration merges working! All you need to do is put "./typings" before "./node_modules/@types".

"typeRoots": ["./typings", "./node_modules/@types"]

Still not working

I solved this issues like this
(req as any).something = object;
it works for me

Same. I can't make it work. Neither solution helps. Yours is an ugly hack but works for sure.

My problem is that VSCode recognizes it, and all is green. But when I try to run it with ts-node, it gives the error.

[HarishAnkolekar24]

The following worked for me:

// project-root/src/types/express/index.d.ts
declare global {
    namespace Express {
        interface Request {
            token?: string
        }
    }
}

And then run

ts-node --files ./src/server.ts

As ts-node does not use files because of slows startup time, we need to tell it explicitly. Hence '--files' is necessary here.

[brunolm]

VSCode gives me:

Augmentations for the global scope can only be directly nested in external modules or ambient module declarations.ts(2669)

[HarishAnkolekar24]

You need to import or export something to indicate that the file is a module.
If you are not importing anything then simply add

export {};

in that file, then the error should be gone.

[shane-js]

To help anyone who is just looking for something else to try here is what worked for me when trying to extend ExpressJS' Request. I had to have tried more than a dozen things before getting this to work:

• Flip the order of what everyone is recommending in the "typeRoots" of your tsconfig.json (and don't forget to drop the src pathing if you have a rootDir setting in tsconfig such as "./src"). Example:

"typeRoots": [
      "./node_modules/@types",
      "./your-custom-types-dir"
]

• Example of custom extension ('./your-custom-types-dir/express/index.d.ts"). I had to use inline import and default exports to use classes as a type in my experience so that is shown too:

declare global {
  namespace Express {
    interface Request {
      customBasicProperty: string,
      customClassProperty: import("../path/to/CustomClass").default;
    }
  }
}

• Update your nodemon.json file to add the "--files" command to ts-node, example:

{
  "restartable": "rs",
  "ignore": [".git", "node_modules/**/node_modules"],
  "verbose": true,
  "exec": "ts-node --files",
  "watch": ["src/"],
  "env": {
    "NODE_ENV": "development"
  },
  "ext": "js,json,ts"
}

[joshuanwafor]

The following worked for me:

// project-root/src/types/express/index.d.ts
declare global {
    namespace Express {
        interface Request {
            token?: string
        }
    }
}

And then run

ts-node --files ./src/server.ts

As ts-node does not use files because of slows startup time, we need to tell it explicitly. Hence '--files' is necessary here.

Worked for me. Thank you so much

[joaoromeira]

Works for me... I add "--files" flag in the run command "ts-node --files index.ts", and create express.d.ts with the follow content.

declare namespace Express {
export interface Request {
user_id: number;
}
}

[galletafromjell666]

An alternative to using the --files tag with ts-node could be adding the ts-node property to the tsconfig.json:

tsconfig.json

{
  "ts-node": {
    "files": true
  },
  "compilerOptions":{
    // ...
  }
}

[pufex]

@galletafromjell666 thanks bro! Worked for me :D