SOURCE

function* helloWorldGenerator() {
    console.log('开始');
  yield 'hello';
  console.log('执行','hello');
  yield 'world';
  console.log('执行','world');
  return 'ending';
}

var hw = helloWorldGenerator();
console.log(hw.next())
console.log(hw.next())
console.log(hw.next())
console.log(hw.next())
console.log(hw.next())
console.log(hw.next())
console.log(hw.next().done == true)

function *foo() {
  yield 1;
  yield 2;
  yield 3;
  yield 4;
  yield 5;
  return 6;
}

for (let v of foo()) {
  console.log(v);
}

function* gen(x){
  var y = yield x + 2;
  return y;
}

var g = gen(1);
console.log(g.next())  // { value: 3, done: false }
console.log(g.next()) // { value: undefined, done: true }

function Point(x, y) {
  this.x = x;
  this.y = y;
}(9,8)

Point.prototype.toString = function () {
  return '(' + this.x + ', ' + this.y + ')';
};


Point.toString2 = function () {
  return '(' + this.x + '/' + this.y + ')';
};

var p = new Point(1, 2);
console.log(p.toString())


var p1 = new Point(3, 4);
console.log(Point.toString2())

console.log(Point.x)