Function overloading

index.ts

export enum Events {
  LOGIN = 'login',
  LOGOUT = 'logout'
}

interface LoginPayload {
  login: true
}

interface LogoutPayload {
  logout: true
}

export function dispatch(event: Events.LOGIN, payload: LoginPayload): void
export function dispatch(event: Events.LOGOUT, payload: LogoutPayload): void
export function dispatch(event: Events, payload: object) {
  switch (event) {
    // do something based on event
  }
}