ReduxIntro5

var a = { name: 'Pilsner', abv: 5.4 };//  Remains untouched
var b = Object.assign({}, a, {abv: 6.7})//  b = { name: 'Pilsner', abv: 6.7 }}

var a = [0, 1, 2]//  Remains untouched
var b = a.concat(3)//  b = [0, 1, 2, 3]
var c = a.filter((val) => != 2)// c = [0, 1, 3]

var a = {name: 'Dave Matthews', songs: [0, 1, 2]}//  Remains untouched
var b = Object.assign({}, a, {name: 'Jack Johnson'});// b = {name: 'Jack Johnson', songs: [0, 1, 2]}
b.songs = a.songs.concat(3);//  b = {name: 'Jack Johnson', things: [0, 1, 2, 3]}