Property '' does not exist on type 'Request<ParamsDictionary>'

Question

When trying to extend the Request interface from the package express to add some custom properties, I'm getting the following typescript error:

TS2339: Property '' does not exist on type 'Request<ParamsDictionary>'.

Do you know how to solve that?

Answer 1

Since a recent update of its typings and dependencies, I found that the following should fix the errors in your application.

In your tsconfig.json

{
  "compilerOptions": {
    //...
    "typeRoots": [
      "./custom_typings",
      "./node_modules/@types"
    ],
  }
// ...
}

And in your custom typings

// custom_typings/express/index.d.ts
declare namespace Express {
    interface Request {
        customProperties: string[];
    }
}