Javascript 如何使承诺在 IE11 中工作

How to make promises work in IE11

提问by Billy Logan

I have a simple code that runs perfectly on every browser except for the Internet Explorer 11. How can I make it work on all browsers?

我有一个简单的代码，可以在除 Internet Explorer 11 之外的所有浏览器上完美运行。如何使其在所有浏览器上运行？

Codepen

代码笔

Thanks in advance.

提前致谢。

'use strict';

let promise = new Promise((resolve, reject) => {

  setTimeout(() => {
    resolve("result");
  }, 1000);
});

promise
  .then(
    result => {
      alert("Fulfilled: " + result);
    },
    error => {
      alert("Rejected: " + error);
    }
  );

回答by jfriend00

If you want this type of code to run in IE11 (which does not support much of ES6 at all), then you need to get a 3rd party promise library (like Bluebird), include that library and change your coding to use ES5 coding structures (no arrow functions, no let, etc...) so you can live within the limits of what older browsers support.

如果您希望这种类型的代码在 IE11（它根本不支持大部分 ES6）中运行，那么您需要获得一个 3rd 方承诺库（如Bluebird），包含该库并更改您的编码以使用 ES5 编码结构（没有箭头功能，没有let，等等...）所以你可以生活在旧浏览器支持的范围内。

Or, you can use a transpiler (like Babel) to convert your ES6 code to ES5 code that will work in older browsers.

或者，您可以使用转译器（如Babel）将您的 ES6 代码转换为适用于旧浏览器的 ES5 代码。

Here's a version of your code written in ES5 syntax with the Bluebird promise library:

这是使用 Bluebird 承诺库以 ES5 语法编写的代码版本：

<script src="https://cdnjs.cloudflare.com/ajax/libs/bluebird/3.3.4/bluebird.min.js"></script>

<script>

'use strict';

var promise = new Promise(function(resolve) {
    setTimeout(function() {
        resolve("result");
    }, 1000);
});

promise.then(function(result) {
    alert("Fulfilled: " + result);
}, function(error) {
    alert("Rejected: " + error);
});

</script>

回答by ScottyG

You could try using a Polyfill. The following Polyfill was published in 2019 and did the trick for me. It assigns the Promise function to the window object.

您可以尝试使用 Polyfill。以下 Polyfill 于 2019 年发布，对我有用。它将 Promise 函数分配给 window 对象。

used like: window.Promisehttps://www.npmjs.com/package/promise-polyfill

使用如下：https: window.Promise//www.npmjs.com/package/promise-polyfill

If you want more information on Polyfills check out the following MDN web doc https://developer.mozilla.org/en-US/docs/Glossary/Polyfill

如果您想了解有关 Polyfill 的更多信息，请查看以下 MDN 网络文档 https://developer.mozilla.org/en-US/docs/Glossary/Polyfill