ts-overmind-declare-module.ts

// src/overmind/index.ts
import { IConfig } from 'overmind'

const config = {
  state: {
    count: 0
  },
  actions: {
    increaseCount({ state }) {
      state.count++;
    },
    decreaseCount({ state }) {
      state.count--;
    }
  }
};

declare module 'overmind' {
  // tslint:disable:interface-name
  interface Config extends IConfig<typeof config> {}
}