zzdjk6

// Selectors

// Select the whole loading state object
export const selectLoadingState = (state: RootState) => state.ui.loading;

// Select whether a given routine is loading
export const selectLoading = (routineType: string) => {
  return createSelector([selectLoadingState], (state: LoadingState) => {
    return !!state[routineType];
  });

zzdjk6

// State

// To know more about Record type, see https://www.typescriptlang.org/docs/handbook/utility-types.html#recordkt
export type LoadingState = Record<string, boolean>;

zzdjk6

// Reducer

export default (state: LoadingState = {}, action: Action<any>): LoadingState => {
  const { type } = action;
  const matches = /(.*)\/(REQUEST|SUCCESS|FAILURE)/.exec(type);

  // Ignore non-routine actions:
  //   A routine action should have one of three suffixes: 
  //   ['/REQUEST', '/SUCCESS', '/FAILURE']
  if (!matches) return state;

zzdjk6

const discount1 = (price, discount) => {
  const final = price * (1 - discount);
  console.log(`V1 -- Original Price: ${price}, Discount: ${discount}, Final Price: ${final}`);
}

discount1(500, 0.5);
discount1(400, 0.5);
discount1(300, 0.5);

const halfPrice1 = price => discount1(price, 0.5);

zzdjk6

// @flow

import React from 'react';

type MapValuesToProps = (values: any) => any;

export const connectToContext = (context: React$Context<any>) => (mapValuesToProps: MapValuesToProps) => (
  Comp: any
) => {
  const wrapped = (props: any) => {

zzdjk6

const sendNativePostRequest = (url, params) => {
  return new Promise((resolve, reject) => {
    const uuid = uuidv4();
    _.set(window, `jsCallbackBridge.promises.${uuid}`, { resolve, reject });

    const body = ''; //TODO: construct body
    window.webkit.messageHandlers.native.postMessage({
        type: 'SEND_HTTP_REQUEST',
        url,
        body,

zzdjk6

import _ from 'lodash';

const resolvePromise = (uuid, resolveData, rejectReason) => {
  const promise = _.get(window, `jsCallbackBridge.promises.${uuid}`);
  if (!promise) {
    return;
  }
  
  const { resole, reject } = {...promise};

zzdjk6

if let error = error {
    let js = "window.jsCallbackBridge.resolvePromise('\(uuid)', null, '\(error.localizedDescription)')"
    DispatchQueue.main.async {
       self.webView?.evaluateJavaScript(js, completionHandler: nil)
    }
    return
}

guard let response = response as? HTTPURLResponse, (200...299).contains(response.statusCode) else {
    let js = "window.jsCallbackBridge.resolvePromise('\(uuid)', null, 'server error')"

zzdjk6

class WebAppViewController: UIViewController {

    var webView: WKWebView?

    override func viewDidLoad() {
        super.viewDidLoad()

        let contentController = WKUserContentController()
        contentController.add(self, name: "native")

zzdjk6

// 1. Define a routine
const FetchDataRoutine: createThunkRoutine<DataType, Error>('FETCH_DATA')
 
// 2. Create a thunk
const fetchData = () => async (dispatch: Dispatch, getState: () => RootState) => {
  dispatch(FetchDataRoutine.request());
  try {
    const data = await api.fetchData();
    dispatch(FetchDataRoutine.success(data));
  } catch (e) {