arrow-functions.js

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

const cube = (x) => {
    return x * x * x;
};

const numbers = [11, 20, 33, 40, 55];

const isEven = (n) => n % 2 === 0;
const halve = (value) => value / 2;

const result = numbers
    .filter(isEven)
    .map(halve)
    .sort();

console.log(result);

const names = [
    { name: "B" },
    { name: "A" }
].map(person => person.name).sort();

console.log(names);

const sayHi = () => console.log("hi");
const add = (a, b) => a + b;

function ViewModel() {
    this.values = [];

    ajax("https://some.api.com/endpoint.json", (values) => {
        this.values = values;
    });
}

block-scoping.js

// Block Scoping
function foo(a, b) {
    if (a > b) {
        let temp = a;
        a = b;
        b = temp;
    }

    console.log(temp);
}

foo(10, 5);

classes.js

/*
var Circle = (function() {
    function Circle(radius) {
        this.radius = radius;
    }

    Circle.prototype.getArea = function() {
        return Math.PI * Math.pow(this.radius, 2);
    };

    return Circle;
})();
*/

class Circle {
    constructor(radius) {
        this.radius = radius;
    }

    get area() {
        return Math.PI * Math.pow(this.radius, 2);
    }

    static unit() {
        return new Circle(1);
    }
}

var circle = new Circle(10);
var area = circle.area;
console.log(area);

var unitCircle = Circle.unit();
console.log(unitCircle);

class Animal {
    constructor(name) {
        this.name;
    }
}

class Cat extends Animal {
    constructor(name) {
        super(name);

        // ...
    }
}

class Dog extends Animal {

}

const cat = new Cat("Sally");

constants.js

const numbers = [1, 2, 3];
numbers.push(4);

console.log(numbers);

const person = {
    name: "Max",
    age: 32
};
person.age++;

// const is ONE-TIME ASSIGNMENT
// not necessarily IMMUTABLE

default-parameters.js

function greet(greeting = "Hello") {
    console.log(`${greeting} DWX 2016!`);
}

function greet(greeting) {
    greeting = greeting || "Hello";

    console.log(`${greeting} DWX 2016!`);
}

greet("Hi");
greet("");

function point(x, y) {
    x = x || 100;
    y = y || 100;

    return { x, y };
}

console.log(point(0, 0));

destructuring-arrays.js

const numbers = [1, 2, 3, 4, 5];
const [head, ...tail] = numbers;

console.log(head);
console.log(tail);

destructuring-objects.js

const point = { x: 10, y: 10, z: 10 };

// Destructuring of objects
function doSomething(point = {}) {
    const { x = 1, y = 2 } = point;
    console.log(x, y);
}

doSomething();
doSomething({});
doSomething({ x: 3 });
doSomething({ x: 3, y: 4 });

enhanced-object-literals.js

const x = 10;
const y = 20;

// Shorthand property syntax
const point = { x, y };

// Method syntax
const person = {
    name: "Max",

    // Previously:
    // sayHi: function() {
    sayHi() {
        console.log(`Hi, I am ${this.name}.`);
    }
};

// Computed property names
const person2 = {
    ["na" + "me"]: "Max"
};

iterators.js

const obj2 = {
    [Symbol.iterator]() {
        let count = 0;
        let done = false;

        return {
            next() {
                if (count > 5) {
                    done = true;
                } else {
                    count++;
                }

                return { done, value: count };
            }
        };
    }
};

for (let x of obj2) {
    console.log(x)
}

loop-binding.js

let actions = [];

for (let i = 0; i < 5; i++) {
    actions.push(function() {
        console.log(i);
    });
}

actions.forEach(function(action) {
    action();
});


// IIFE
(function() {

}());

rest-parameters.js

function nonNegative(...args) {
    return args.filter(function(value) {
        return value >= 0;
    });
}

console.log(
    nonNegative(1, -2, 3, -4, 5)
);

spread-operator.js

const listA = [1, 2, 3];
const listB = [4, 5];

// Array literals
const listC = [0, ...listA, ...listB, 6];
console.log(listC);

// Function calls
const values = [10, 30, 20, 40, 0];
const max = Math.max(...values);
console.log(max);

symbols.js

const symbol = Symbol();
console.log(typeof symbol);
console.log(symbol);

const obj = { bar: 43 };
obj[symbol] = "foo";
console.log(obj[symbol]);
console.log(JSON.stringify(obj));
console.log(Object.getOwnPropertySymbols(obj));

template-literals.js

const firstName = "Peter";
const lastName = "Pan";

const fullName1 = firstName + " " + lastName;
const fullName2 = `${firstName} ${lastName}`;
console.log(fullName2);

// Multiline strings
const text = `line 1
line 2
line 3`;