Simple demo of generators in JavaScript

generator_demo.js

function print(obj) {
  console.log(JSON.stringify(obj, null));
}

function* gen() {
  var x = yield 'a';
  var y = yield 'b';
  var z = yield 'c';

  return [x, y, z];
}

var iter = gen();

print(iter.next('d')); //{"value":"a","done":false}
print(iter.next('e')); //{"value":"b","done":false}
print(iter.next('f')); //{"value":"c","done":false}
print(iter.next('g')); //{"value":["e","f","g"],"done":true}