Promise

---

什么是Promise

• Promise 对象用于表示一个异步操作的最终完成 (或失败), 及其结果值.

网址

网址2

const p = new Promise((resolve, reject) => {
  setTimeout(() => {
    resolve('foo');
  }, 300);
});

p.then((value) => {
  console.log(value);
  // expected output: "foo"
});

console.log(p);
// expected output: [object Promise]

语法

new Promise( function(resolve, reject) {...} /* executor */  );