Create-React-App 在 IE11 上显示空白屏幕。 错误：SCRIPT5009：'WebSocket' 未定义和 SCRIPT5009：'Promise' 未定义

Question

CRA works fine on every other browser but displaying blank screen on IE. I have tried installing react-app-polyfill 2.0 and 1.0.6, putting import "react-app-polyfill/ie11" import "react-app-polyfill/stable" at the top of src/index.js file. As well as putting "ie 11" in the browserList for dev and prod env. I also removed the.cache file in node_modules and still same error pops up. Here is my code:

package.json file dependencies

paackage.json file browserList

Polyfill imports

Here are the error messages I am getting:

Whole error

'WebSocket'is undefined points to this

'Promise' is undefined error points to this

Answer 1

As we can see that you had already added the react-app-polyfill and added the "ie 11" in the browser list.

I suggest you keep those settings and refer to the steps below.

If this is a newly created app and not working with IE 11 then I suggest you install core-JS using the command npm install core-js and add import 'core-js/stable' on the first line in the index.js file.

The starting of the index.js file should look like below.

import 'core-js/stable';
import 'react-app-polyfill/ie11';
import 'react-app-polyfill/stable';
import React from 'react';
import ReactDOM from 'react-dom';

After that delete the .cache folder under node_modules and again try to run the project. It may help you to run it in IE 11.

If your React app was working with IE 11 and you got this issue after adding some code then I suggest you try to provide detailed information about it. It can help us to understand the issue properly.

Thanks for your understanding.