Promiseコード片

cached.js

let hoge = null;
const getHoge = () => hoge
  ? Promise.resolve(hoge)
  : new Promise((resolve, reject) => {
    someAsnycWork((data) => {
      hoge = data;
      resolve(data);
    })
  });

export const doHoge = () =>
  getHoge()
    .then((hoge) => (someWorkWithHoge(hoge)));