alexnm

// Basic syntax examples
var add = ( a, b ) => a + b; // function( a, b ) { return a + b; }
var increment = a => a + 1; // function( a ) { return a + 1; }
var random = ( ) => Math.random( ) // function( ) { return Math.random( ); } 

// Functional programming unleashed
var array = [ 'alice', 'bob', 'charles', 'dan', 'eugene', 'felicity' ];
var longNames = array.filter( name => name.length > 3 );
var longNamesIndexes = longNames.map( ( name, index ) => index );
var sumOfIndexes = longNamesIndexes.reduce( add );

alexnm

if ( condition ) {
  let x = 1;
  const y = 2;
  var z = 3;
  
  x = 4;
  y = 5;
  z = 6;
  
  console.log( x ); // 4

alexnm

// A factory method which returns an object
const factory = ( ) => { a: 1, b: 2 } 
const { a, b } = factory( ); // a = 1, b = 2

// A method that takes a Person object as a parameter and returns the full name
// firstName and lastName get destructured into variables inside the function
const fullName = ( { firstName, lastName } ) => firstName + ' ' + lastName;
const person = { 
  firstName: 'Alex', 
  lastName: 'M', 

alexnm

// Default parameters
const add = ( a, b = 1 ) => a + b;
add( 2, 4 ); // 6 - add
add( 3 ); // 4 - increment

// Rest parameters
const add = ( ...args ) => args.reduce( ( a, b ) => a + b );
add( 2, 4 ); // 6
add( 1, 2, 3, 4, 5 ); // 15
add( 5 ); // 5

alexnm

function* fibonacci( ){
  let n1 = 0;
  let n2 = 1;
  while ( true ) {  
    const current = n1;
    n1 = n2;
    n2 = current + n1;
    yield current;
  }
}

alexnm

function* ( ) {
  const user = yield getUser( ); // async api call
  const cart = yield getShoppingCart( user ); // async api call
  const items = yield getItems( user, cart ); // aync api call
}

alexnm

class Rectangle extends Shape {
  constructor( x, y, color ) {
    super( color );

    this.x = x;
    this.y = y;
    this.color = color
  }
  
  get length( ) {

alexnm

const product = {
  name: 'T-Shirt',
  price: 9.99,
  color: 'red',
  size: 'M',
  stock: 4,
  updateStock: function( newStock ) {
    this.stock += newStock;
  }
};

alexnm

function Product( initialStock ) {
  let stock = initialStock;
  
  /* ... extra fields omitted for simplicity ... */
  
  this.updateStock = function( newStock ) {
    stock += newStock;
  }
  this.getStock = function( ) {
    return stock;

alexnm

function createProduct( initialStock ) {
  let stock = initialStock;
  
  return {
    /* ... extra fields omitted for simplicity ... */
    updateStock( newStock ) {
      stock += newStock;
    },
    getStock( ) {
      return stock;