vldvel

function * generator(arr) {
  for (const el in arr)
    yield el;
}

const gen = generator([0, 1, 2]);

for (const g of gen) {
  console.log(g); // 0 -> 1 -> 2
}

vldvel

function * generator() {
  yield 1;
  return 2;
  yield 3; // we will never reach this yield
}

const gen = generator();

gen.next(); // {value: 1, done: false}
gen.next(); // {value: 2, done: true}

vldvel

function * anotherGenerator(i) {
  yield i + 1;
  yield i + 2;
  yield i + 3;
}

function * generator(i) {
  yield* anotherGenerator(i);
}

vldvel

const strings = document.querySelectorAll('.string');
const btn = document.querySelector('#btn');
const className = 'darker';

function * addClassToEach(elements, className) {
  for (const el of Array.from(elements))
    yield el.classList.add(className);
}

const addClassToStrings = addClassToEach(strings, className);

vldvel

function * generator() {
  yield 1;
  yield 2;
  yield 3;
}

const gen = generator();

gen.throw('Something bad'); // Error Uncaught Something bad
gen.next(); // {value: undefined, done: true}

vldvel

function * generator() {
  yield 1;
  yield 2;
  yield 3;
}

const gen = generator();

gen.return(); // {value: undefined, done: true}
gen.return('Heeyyaa'); // {value: "Heeyyaa", done: true}

vldvel

function * generator() {
  yield 1;
  yield 2;
  yield 3;
}

const gen = generator();

gen.next(); // {value: 1, done: false}
gen.next(); // {value: 2, done: false}

vldvel

function * generator(arg = 'Nothing') {
  yield arg;
}

const gen0 = generator(); // OK
const gen1 = generator('Hello'); // OK
const gen2 = new generator(); // Not OK

generator().next(); // It will work, but every time from the beginning

vldvel

function * generator() {
  yield 5;
}

const gen = generator();

gen.next(); // {value: 5, done: false}
gen.next(); // {value: undefined, done: true}
gen.next(); // {value: undefined, done: true} - all other calls will produce the same result

vldvel

function * withYield(a) {
  let b = 5;
  yield a + b;
  b = 6; // it will be re-assigned after first execution
  yield a * b;
}

const calcSix = withYield(6);

calcSix.next().value; // 11