Pick only one

index.d.ts

type RequireOnlyOne<T, Keys extends keyof T = keyof T> =
  Pick<T, Exclude<keyof T, Keys>>
  & {
    [K in Keys]-?:
      Required<Pick<T, K>>
      & Partial<Record<Exclude<Keys, K>, undefined>>
  }[Keys]

type Events = 'play' | 'pause' | 'ready' | 'seek' | 'end';

type ABC = {
  on: (cb: RequireOnlyOne<Record<Events, () => void>>) => void
}

const abc: ABC = {
  on: (cb) => {}
}



abc.on({ ready: () => console.log('yes') })
abc.on({ play: () => console.log('no'), pause: () => console.log('no') })