I am currently working on a typescript project that uses express to manage backend API calls, however when trying to assign these custom properties, typescript raises an error stating that these properties simply do not exist.

I have tried to create a custom types subdirectory within my project to manage all the extra attributes as well as several custom types I may add later on during the project’s development. I have tried this and setup the project like so

src
│   index.ts
│   
├───config
│       database.ts
│       
├───routes
│       login.ts
│       router.ts
│       signup.ts
│       upload.ts
│       
├───types
│       express.d.ts
│
└───utils
        auth.ts

With all other configuration files located at the top level (such as package.json or package-lock.json). To add the types subdirectory I have modified my tsconfig.json with the following contents

{
  "compilerOptions": {
    "target": "es2016",
    "module": "commonjs",
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    "strict": true,
    "skipLibCheck": true,
    "typeRoots": [
      "./node_modules/@types",
      "./src/types"
    ]
  },
  "exclude": [
    "node_modules",
    "dist"
  ]
}

And the type file with the contents:

// express.d.ts
import { Request } from 'express';

interface User {
    id: number,
    username: string,
    token_type: string
}

declare global {
    namespace Express {
        interface Request {
            files?: any,// Replace `any` with the appropriate type if you know it
            user: User
        }
    }
}

But an error is raised when trying to access or modify the newly assigned attributes essentially saying it doesn’t exist

C:UsersMeAppDataRoamingnpmnode_modulests-nodesrcindex.ts:859
    return new TSError(diagnosticText, diagnosticCodes, diagnostics);
           ^
TSError: ⨯ Unable to compile TypeScript:
src/routes/upload.ts:29:14 - error TS2339: Property 'files' does not exist on type 'Request<ParamsDictionary, any, any, ParsedQs, Record<string, any>>'.

29     if (!req.files || Object.keys(req.files).length === 0) {
                ~~~~~
src/routes/upload.ts:29:39 - error TS2339: Property 'files' does not exist on type 'Request<ParamsDictionary, any, any, ParsedQs, Record<string, any>>'.

29     if (!req.files || Object.keys(req.files).length === 0) {
                                         ~~~~~
src/routes/upload.ts:32:22 - error TS2339: Property 'files' does not exist on type 'Request<ParamsDictionary, any, any, ParsedQs, Record<string, any>>'.

32     const file = req.files.Filename
                        ~~~~~
src/routes/upload.ts:37:13 - error TS2339: Property 'user' does not exist on type 'Request<ParamsDictionary, any, any, ParsedQs, Record<string, any>>'.

37         req.user!.id,
               ~~~~

    at createTSError (C:UsersMeAppDataRoamingnpmnode_modulests-nodesrcindex.ts:859:12)
    at reportTSError (C:UsersMeAppDataRoamingnpmnode_modulests-nodesrcindex.ts:863:19)
    at getOutput (C:UsersMeAppDataRoamingnpmnode_modulests-nodesrcindex.ts:1077:36)
    at Object.compile (C:UsersMeAppDataRoamingnpmnode_modulests-nodesrcindex.ts:1433:41)
    at Module.m._compile (C:UsersMeAppDataRoamingnpmnode_modulests-nodesrcindex.ts:1617:30)
    at Module._extensions..js (node:internal/modules/cjs/loader:1295:10)
    at Object.require.extensions.<computed> [as .ts] (C:UsersMeAppDataRoamingnpmnode_modulests-nodesrcindex.ts:1621:12)
    at Module.load (node:internal/modules/cjs/loader:1091:32)
    at Function.Module._load (node:internal/modules/cjs/loader:938:12)
    at Module.require (node:internal/modules/cjs/loader:1115:19) {
  diagnosticCodes: [ 2339, 2339, 2339, 2339 ]
}

I’ve been looking online and can’t seem to find the answer, all help is appreciated! 😀