Simple demo of a generator function

generator_function.js

function square(x) {
  return x * x;
}

function* sumSquares(values) {
  let result = 0;
  for (value of values) {
    const nextIncrement = yield square(value);
    console.log(`inside sumSquares: ${nextIncrement}`);
    result += nextIncrement;
  }
  return result;
}

const generator = sumSquares([1, 2, 3, 4, 5])

let result = generator.next();
console.log(result);
while (!result.done) {
  result = generator.next(result.value);
  console.log(result);
}

console.log(result.value);