模拟实现一个 Promise.finally

类别：js / 日期：2023-05-04 / 浏览：227 / 评论：0

Promise.prototype.finally = function (callback) {
  let P = this.constructor;
  return this.then(
    (value) => P.resolve(callback()).then(() => value),
    (reason) =>
      P.resolve(callback()).then(() => {
        throw reason;
      })
  );
};