Vuex action helper

action.ts

import {
  INIT_SOME_DATA,
  ADD_SOME_DATA,
  MOVE_SOME_DATA,
  REMOVE_SOME_DATA,
  UPDATE_SOME_DATA
} from '../mutation_types'

import { ISomeData } from '../model/some_data'

import { action } from '../generators/helper'

export const initSomeData = action(
  INIT_SOME_DATA,
  (data: ISomeData[]) => ({ data })
)

export const addSomeData = action(ADD_SOME_DATA)

export const moveSomeData = action(
  MOVE_SOME_DATA,  
  (index: number, offset: number) => ({ index, offset })
)

export const removeSomeData = action(
  REMOVE_SOME_DATA,  
  (index: number) => ({ index })
)

export const updateSomeData = action(
  UPDATE_SOME_DATA,
  (key: string, value: string) => ({ [key]: value })
)

helper.ts

import { Store } from 'vuex'

type Action0 = (s: Store<any>) => void;
type Action1<T> = (s: Store<any>, t: T) => void;
type Action2<T, U> = (s: Store<any>, t: T, u: U) => void;
type Action = (s: Store<any>, ...args: any[]) => void;

export function action<T, P>(type: string, creator: (t: T) => P) : Action1<T>
export function action<T, U, P>(type: string, creator: (t: T, u: U) => P) : Action2<T, U>
export function action<P>(type: string) : Action0
export function action<P>(type: string, creator?: (...args: any[]) => P | undefined) : Action {
  if (typeof creator === 'undefined') {
    creator = () => void 0
  }

  return ({ dispatch }, ...args) => dispatch({
    type,
    payload: creator!(...args)
  })
}