types-kit.mergeexclusive.md

Home > types-kit > MergeExclusive

MergeExclusive type

Create a type that has mutually exclusive keys.

Signature:

export type MergeExclusive<T, U> = IsObject<T | U> extends true
  ? (Without<T, U> & U) | (Without<U, T> & T)
  : T | U

References: IsObject, Without

Example

    interface Props {
      a: number
    }
    interface Props2 {
      b: string
    }
    let foo: MergeExclusive<Props, Props2>;
    foo = { a: 1 } // Works
    foo = { b: 'foo' } // Works
    foo = { a: 1, b: 'foo'} // Error