LearnES6part2 created by alexspark - https://repl.it/@alexspark/LearnES6part2

LearnES6part2.js

// iterators
const fib = {
  [Symbol.iterator]() {
    let pre = 0, cur = 1;
    return {
      next() {
        [ pre, cur ] = [cur, pre + cur];
        return {
          done: false, value: cur
        };
      }
    };
  }
};

for (let n of fib) {
  if (n > 100) { break; }
  console.log(n);
}

// generators
const fibb = {
  *[Symbol.iterator]() {
    let pre = 0, cur = 1;
    for (;;) {
      [ pre, cur ] = [ cur, pre + cur];
      yield cur
    }
  }
}

for (let n of fibb) {
  if (n > 100) { break; }
  console.log(n);
}

// function generator
const steps = function*(start, end) {
  while (start <= end) {
    yield start
    start += 1;
  }
};

for (let n of steps(1, 25)) {
  console.log(n);
}

// generator matching
let numbers = [ ...steps(100, 110)];
let [n1, n2, n3, ...rest] = steps(200, 210);

console.log(...numbers);
console.log(n1, n2, n3, ...rest);

// generator methods
class Cat {
  constructor(name, owner) {
    this._name = name;
    this._owner = owner;
    this._meowCount = 0;
  }
  set name(n) { this._name = n; }
  get name() { return this._name; }
  * meow() {
    for(;;) {
      this._meowCount += 1;
      console.log(`MEOW! (${this._meowCount})`)
      yield this._meowCount;
    }
  }
}

const b = new Cat('bella', 'alex')
for (m of b.meow()) {
  if(m > 10) { break; }
}