Merge discriminated union props for better easier destructuring

example.ts

type SomeProps =
  | { action: "START" }
  | { action: "STOP"; time: number }
  | { action: "PAUSE"; time: number; ref: { current: any } };

function useExample(props: SomeProps) {
  let {
    action, // "START" | "STOP" | "PAUSE"
    time, // number | undefined,
    ref // { current: any } | undefined
  } = props as Merge<SomeProps>;
  return { action, time, ref };
}

// This strategy of merging a discriminated union into a single object type
// courtesy of https://dev.to/lucianbc/union-type-merging-in-typescript-9al
type AllKeys<T> = T extends any ? keyof T : never;
type NonCommonKeys<T extends object> = Subtract<AllKeys<T>, keyof T>;
type PickType<T, K extends AllKeys<T>> = T extends {
  [k in K]?: any;
}
  ? T[K]
  : undefined;
type PickTypeOf<T, K extends string | number | symbol> = K extends AllKeys<T>
  ? PickType<T, K>
  : never;
type Merge<T extends object> = { [k in keyof T]: PickTypeOf<T, k> } & //
  { [k in NonCommonKeys<T>]?: PickTypeOf<T, k> };
type Subtract<A, C> = A extends C ? never : A;