ES2015 features

arrowFunctions.js

// Expressões (Expression bodies)
var odds = evens.map(v => v + 1);
var nums = evens.map((v, i) => v + i);

// Declarações (Statement bodies)
nums.forEach(v => {
  if (v % 5 === 0)
    fives.push(v);
});

// Referência léxica ao *this* (Lexical this)
var bob = {
  _name: "Bob",
  _friends: [],
  printFriends() {
    this._friends.forEach(f =>
      console.log(this._name + " knows " + f));
  }
};