1367-remove-index-signature.ts

/*
  1367 - Remove Index Signature
  -------
  by hiroya iizuka (@hiroyaiizuka) #medium #object-keys

  ### Question

  Implement `RemoveIndexSignature<T>` , exclude the index signature from object types.

  For example:

  ```

  type Foo = {
    [key: string]: any;
    foo(): void;
  }

  type A = RemoveIndexSignature<Foo>  // expected { foo(): void }

  ```

  > View on GitHub: https://tsch.js.org/1367
*/

/* _____________ Your Code Here _____________ */

type RemoveIndexSignature<T> = { [
    k in keyof T as string extends k
        ? never
        : number extends k
            ? never
            : symbol extends k
                ? never : k
    ]: T[k]
};

/* _____________ Test Cases _____________ */
import type { Equal, Expect } from '@type-challenges/utils'

type Foo = {
    [key: string]: any
    foo(): void
}

type Bar = {
    [key: number]: any
    bar(): void
    0: string
}

const foobar = Symbol('foobar')
type FooBar = {
    [key: symbol]: any
    [foobar](): void
}

type Baz = {
    bar(): void
    baz: string
}

type cases = [
    Expect<Equal<RemoveIndexSignature<Foo>, { foo(): void }>>,
    Expect<Equal<RemoveIndexSignature<Bar>, { bar(): void; 0: string }>>,
    Expect<Equal<RemoveIndexSignature<FooBar>, { [foobar](): void }>>,
    Expect<Equal<RemoveIndexSignature<Baz>, { bar(): void; baz: string }>>,
]

/* _____________ Further Steps _____________ */
/*
  > Share your solutions: https://tsch.js.org/1367/answer
  > View solutions: https://tsch.js.org/1367/solutions
  > More Challenges: https://tsch.js.org
*/