guangLess

const todo = (state, action) => {
  switch (action.type) {
      case 'ADD_TODO':    
      return {
            id: action.id,
            completed:false,
            text: action.text,
        };
      case 'TOGGLE_TODO':
       if(state.id !== action.id){

guangLess

let list = [2,3,1];

const addCounter = (list)=>{
  return[...list, 0];
}

const removeCounter = (list, index) => {
  return [
    ...list.slice(0,index),
    ...list.slice(index+1)

guangLess

const counter = (state = 0, action) => {
  switch (action.type){
    case 'INCREMENT' : 
        return state + 1;
     case 'DECREMENT' :
        return state -1;
    default:
      return state;
  }
}

guangLess

import React from 'react';
import Footer from './Footer.js';
import Sidebar from './Sidebar.js';
import AllAlbums from './AllAlbums.js';
import SingleAlbum from './SingleAlbum.js'
import axios from 'axios';

export default class Main extends React.Component {
    constructor(props) {
        super(props);

guangLess

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as! LineTableViewCell
        let eachLine = subwayDataStore.subwayArrayList[indexPath.row]
Optional option 1 : 
        if let iconName = eachLine.letter {
        cell.iconLabel.image = UIImage(named:iconName.lowercaseString)
        }
Optional option 2 : 
        let imageName = eachLine.letter.map {_ in 
             eachLine.letter!.lowercaseString

guangLess

- (void)viewDidLoad {
    [super viewDidLoad];

    NSArray *germanMakes = @[@"A"];
    
    NSArray * fin = [self sortMidtoFront:germanMakes];
    NSLog(@"fin = [%@]",fin);
    
    NSLog(@"testing Number is %lu",(unsigned long)[self checkMidNumber:2]);