Typescript: How to type the Dispatch in Redux

Question

For example I want to remove the dispatch: any here:

export const fetchAllAssets = () => (dispatch: any) => {
  dispatch(actionGetAllAssets);
  return fetchAll([getPrices(), getAvailableSupply()]).then((responses) =>
    dispatch(actionSetAllAssets(formatAssets(responses))));
}

There are 2 actions I dispatch above, actionsGetAllAssets and actionsSetAllassets.

Here are the interfaces and actionCreators for both:

// Interfaces
interface IActions {
  GET_ALL_ASSETS: string;
  SET_ALL_ASSETS: string;
  GET_MARKET_PRICES: string;
  SET_MARKET_PRICES: string;
  ADD_COIN_PORTFOLIO: string;
  ADD_COINS_PORTFOLIO: string;
  UPDATE_COIN_PORTFOLIO: string;
  REMOVE_COIN_PORTFOLIO: string;
} 

interface IGetAllAssets {
  type: IActions['GET_ALL_ASSETS'];
  loading: boolean;
}

interface ISetAllAssets {
  type: IActions['SET_ALL_ASSETS'];
  assets: IAsset[];
  loading: boolean;
}

// ACTION CREATORS
const actionGetAllAssets = () => ({
  type: Actions.GET_ALL_ASSETS,
  loading: true
});

const actionSetAllAssets = (data: any) => ({
  type: Actions.SET_ALL_ASSETS,
  assets: data,
  loading: false
});

So then I tried the following:

export const fetchAllAssets = () => (dispatch: IGetAllAssets | ISetAllAssets) => {
  console.log('fetchAllAssets', dispatch);
  dispatch(actionGetAllAssets);
  return fetchAll([getPrices(), getAvailableSupply()]).then((responses) =>
    dispatch(actionSetAllAssets(formatAssets(responses))));
}

However it produces this Typescript error:

Cannot invoke an expression whose type lacks a call signature. Type 'IGetAllAssets | ISetAllAssets' has no compatible call signatures.ts(2349)

Thoughts? Or is there a different way to type a dispatch event?

Answer 1

The Redux typings have a generic Dispatch<A> type you can use, where A is the type of action.

export const fetchAllAssets = () => (dispatch: Dispatch<IGetAllAssets | ISetAllAssets>) => {
  // ...
}