effects.ts

import {getType} from 'typesafe-actions';

import {getSomething} from '@api';
import {fetchSomething} from '@actions';
import {AppState} from '@types';

async function handleFetchSomething({dispatch, getState, action, nextDispatchAsync}) {
	const state: AppState = getState();
	const params = buildParams(action.payload,state);
	try {
		const response = await getSomething(params);
		dispatch(fetchSomething.success(response.data))
	} catch (e) {
		dispatch(fetchSomethingfailure(e.toString()))
	}
}
export default [
	{action: getType(fetchSomething.request), effect: handleFetchSomething}
]

ts-actions.tsx

import React from 'react';
import {createAsyncAction, createStandardAction, getType} from 'typesafe-actions';

export interface FetchSomethingArguments {
	// ...
}

export interface SomethingType {
	// ...
}

export const appSetNavBarOpen = createStandardAction('APP_SET_NAV_BAR_OPEN')<boolean>();

export const appFetchSomething = createAsyncAction(
	'APP_FETCH_SOMETHING_REQUEST',
	'APP_FETCH_SOMETHING_SUCCESS',
	'APP_FETCH_SOMETHING_FAILURE'
)<FetchSomethingArguments, SomethingType, Error>();

export interface AppState {
	navBarOpen: boolean
}

const DefaultAppState = {
	navBarOpen: false
};

const appReducer = (state: AppState = DefaultAppState, action: any) => {
	switch (action.type) {
		case getType(appSetNavBarOpen):
			// action.payload gets narrows to the FetchSomethingArguments type
			return {
				...state,
				tocOpen: action.payload
			};
		case getType(appFetchSomething.request):
			return {
				// Request State
			};
		case getType(appFetchSomething.success):
			return {
				// Success State
			};
		case getType(appFetchSomething.failure):
			return {
				// Failure State
			};
	}
};

const SomeComponent = () => {
	const getSomethingParams = {};
	return <button onClick={() => appFetchSomething.request(getSomethingParams)}/>
};