类中静态代码块和静态属性值_承诺和静态值

- 日理万妓 2023-02-21 14:30 13阅读 0赞

类中静态代码块和静态属性值

Async can throw a real wrench into the cogs of our programming workflows, all despite the fact that async is the modern JavaScript pattern. While [async/await][async_await] helps, there's sometimes confusion about the way to have a single function that returns a value whether it exists or needs a Promise to retrieve.

尽管事实上异步是现代JavaScript模式，但Async确实可以使我们的编程工作流程陷入困境。 尽管[异步/等待][async_await]会有所帮助，但有时对于使单个函数返回值(无论该值是否存在还是需要Promise)的方式有些困惑。

The key thing to remember is that functions declared as `async` automatically return a Promise, so you don't need explicity return the existing content with `Promise.resolve(content)`:

要记住的关键是，声明为`async`函数会自动返回Promise，因此您无需通过`Promise.resolve(content)`显式地返回现有内容：

async function getValueOrFetch(ojbOrInfo) {
      // If the value exists, immediately return it
      if(ojbOrInfo) {
        return ojbOrInfo;
      }
      // Return the promise-based info
      return asyncFunctionToGetInfo(ojbOrInfo);
    }

Let's look at a real life example: returning cached contents instead of doing a `fetch` call to retrieve them:

让我们看一个真实的例子：返回缓存的内容，而不是执行`fetch`调用来检索它们：

My main goal with this post is making you understand that `return Promise.resolve(data)` isn't needed with async functions -- you can simply return the value and it will be wrapped in a promise!

我写这篇文章的主要目的是让您了解异步函数不需要`return Promise.resolve(data)` －您只需返回该值，它将包装在一个Promise中！

> 翻译自: [https://davidwalsh.name/promises-and-static-values][https_davidwalsh.name_promises-and-static-values]

类中静态代码块和静态属性值

[async_await]: https://davidwalsh.name/async-await
[https_davidwalsh.name_promises-and-static-values]: https://davidwalsh.name/promises-and-static-values