Literator가 유용한 이유

function sync(iterable, depth) {
  const iterator = iterable[Symbol.iterator]();
  const iteratorStack = [iterator];
  return {
    [Symbol.iterator]() {
      return this;
    },
    next() {
      while (iteratorStack.length > 0) {
        const currentIterator = last(iteratorStack);
        const { value, done } = currentIterator.next();
        if (done) {
          iteratorStack.pop();
          continue;
        }
        if (isFlatAble(value) && iteratorStack.length < depth + 1) {
          iteratorStack.push(value[Symbol.iterator]());
          continue;
        }
        return {
          done: false,
          value,
        };
      }
      return {
        done: true,
        value: undefined,
      };
    },
  };
}

function isIterable(valaue) {
  return (
    typeof (a === null || a === void 0 ? void 0 : value[Symbol.iterator]) ===
    "function"
  );
}

function someFunction(value) {
  let weight = 1;
  while (true) {
    value + 1;
  }
}

function* someGenerator(value) {
  let weight = 1;
  while (true) {
    yield value + weight++;
  }
}

const generator = someGenerator(1);

console.log(generator.next().value); // 2
console.log(generator.next().value); // 3
console.log(generator.next().value); // 4
// 필요한 만큼만 값을 생성하고 사용할 수 있습니다.