Is there a way to remove all occurrences of the "__typename" property in Typescript?

Question

I want to remove all occurrences of "__typename" from dictionary "data". I used one of the function from this stackoverflow post: How to remove all instances of a specific key in an object? and it outputs the correct answer but my compiler displays this error message. I am new to Typescript and I am having a hard time finding a solution.

Code snippet:

import * as R from ramda;

// Dictionary "data"
const data = {
    "subscription": {
        "id": "10",
        "subscribers": [
            {
                "id": "2017",
                "username": "potato1",
                "__typename": "UserType"
            },
        ],
        "unsubscribers": [
            {
                "id": "2022",
                "username": "potato2",
                "__typename": "UserType"
            }
        ],
        "__typename": "SubscriptionType"
    },
    "__typename": "Subscribe"
};

// Function from linked stackoverflow post, works but get a syntax error (see screenshot)
const removePropDeep = R.curry((prop, data) =>
    R.when(
        R.is(Object),
        R.pipe(R.dissoc(prop), R.map(removePropDeep(prop))),
        data
    )
);

console.log(removePropDeep("__typename", data));

Expected:

{
    "subscription": {
        "id": "10",
        "subscribers": [
            {
                "id": "2017",
                "username": "potato1",
            },
        ],
        "unsubscribers": [
            {
                "id": "2022",
                "username": "potato2",
            }
        ],
    },
};

Error message:

"Function implicitly has return type 'any'
because it does not have a return type annotation
and is referenced directly or indirectly
in one of its return expressions."

Please do not link _images_ of error messages. Instead copy and paste the relevant output to your question. See http://idownvotedbecau.se/imageofanexception/ — Emma, Feb 17 '22 at 00:12
`__typename` is a private field needed in (e.g.) apollo to understand the schema, you shouldn't really need to remove it IMHO... however, please take a look at https://stackoverflow.com/a/51380645/4099454 — Hitmands, Feb 17 '22 at 13:54

Ori Drori · Answer 1 · 2022-02-17T22:49:00.353

You'll need to create a function overload definition using an interface, because the function is curried. I've used the same definition of R.dissoc (sandbox).

Note: I've replaced R.map with R.mapObjIndexed because TS has a hard time infering that in this case R.map iterates an object.

interface iRemovePropDeep {
  <T extends object, K extends keyof T>(prop: K, obj: T): Omit<T, K>;
  <K extends string | number>(prop: K): <T extends object>(
    obj: T
  ) => Omit<T, K>;
}

const removePropDeep: iRemovePropDeep = curry((prop, data) =>
  when(
    is(Object),
    pipe(dissoc(prop), mapObjIndexed(removePropDeep(prop))),
    data
  )
);

Is there a way to remove all occurrences of the "__typename" property in Typescript?

1 Answers1