console.log([1,2,3,4].map(function(x) {
    return x * 2
}));
//[2,4,6,8]

var square = function(x){ return x*x; };

console.log(square(4)); //16
console.log(square(3)); //9

var name = "Bob";
var bob = {
    name: name,
    friends: ["John", "Tom"],
    printFriends: function() {
        this.friends.forEach(function(f)
        {
            console.log(this.name + " knows " + f);
        });
    }
};

bob.printFriends();
//TypeError: Cannot read property 'name' of undefined

function() {
  {
    console.log(x); //should throw a ReferenceError
    let x = "start";
    y = "start";
    console.log(x,y); // start start
    {
      const z = "permanent";
      //z = "can't touch this";
      x = "inner";
      var y = "works everywhere";
      console.log(x,y,z); // inner works everywhere permanent
    }
    //let x = "new value"; //illegal
  }
  //x = "end";
  y = "end";
  console.log(y); // end
}();

class Vehicle {
    constructor(name) {
        this.kind = 'Vehicle';
        this.name = name;
    }

    printName() {
        console.log(this.name);
    }
}

class Car extends Vehicle {
    constructor(name) {
        super(name);
        this.kind = 'Car';
    }
}

console.log(`In JavaScript '\t\t' is a couple of tabs.`);
// In JavaScript '         ' is a couple of tabs.
console.log(`In JavaScript this is
 not legal.`);
// In JavaScript this is
// not legal.

var name = "Bob", time = "today";
console.log(`Hello ${name}, how are you ${time}?`);
// Hello Bob, how are you today?

var car = {
 make: "Mazda",
 model: "RX-8",
 production: [2007,2008,2009]
};
console.log(`Production started in ${car.production[0]}.`);
// Production started in 2007.

var [a, , b, c=4] = [1,2,3];
console.log(a,b,c); // 1 3 4

var {w,x,y,z:surprise} = {x:"this", y:"is", z:"amazing"}
console.log(w,x,y,surprise); // undefined 'this' 'is' 'amazing'

var getPerson = () => { return {name: "Kuba", company:"ABB"} };

var {name: myName} = getPerson();
console.log(myName); // Kuba

function g({name: x, surname}) {
    console.log(x, surname);
}
g({name: "Tom", surname: "Jones"}); // Tom Jones

function f(x, y=12, z=2*y) {
    console.log(x,y,z);
}
f(1,2,3); // 1 2 3
f(5,8); // 5 8 16
f(4); // 4 12 24


function g(x, ...y) {
    console.log(y);
}
g(3, "hello", true); // ["hello", true]


function h(x, y, z) {
    console.log(x + y + z);
}
h(...[1,2,3]); // 6

// lib/math.js
export function sum(x, y) {
    return x + y;
}
export var pi = 3.141593;

// app.js
import * as math from "lib/math";
alert("2pi = " + math.sum(math.pi, math.pi));

// otherApp.js
import {sum, pi} from "lib/math";
alert("2pi = " + sum(pi, pi));

// lib/math.js
export function sum(x, y) {
    return x + y;
}
export var pi = 3.141593;

// lib/mathplusplus.js
export * from "lib/math";
export var e = 2.71828182846;
export default function(x) {
    return Math.exp(x);
}

// app.js
import exp, {pi, e} from "lib/mathplusplus";
alert("e**pi + e = " + (exp(pi) + e) );