Typescript Redux generic Action

redux.d.ts

// store/redux.d.ts

import {Action as ReduxAction} from 'redux'

export interface Action<
  T extends string, 
  P = undefined
> extends ReduxAction {
  type: T
  payload: P
}

// example use
const TOGGLE = 'toggle'
interface ActionToggle extends Action<typeof TOGGLE> {}

const ADD = 'add'
interface ActionAdd extends Action<typeof ADD, number> {}