如果你正在使用ES6 JavaScript导入:

安装cross-env 在包中。将“test”:“jest”改为“test”:“cross-env NODE_OPTIONS=——experimental-vm-modules jest” 更多的包装。Json，添加这些:

    ...,
    "jest": {
        "transform": {}
    },
    "type": "module"

解释:

Cross-env允许在不更改NPM命令的情况下更改环境变量。接下来，在文件包中。你改变你的npm命令来启用实验性的ES6对Jest的支持，并配置Jest来做到这一点。

我的解决方案是在运行nodemon时包含babel-node路径，如下所示:

nodemon node_modules/.bin/babel-node index.js

你可以加入你的套餐。Json脚本如下:

debug: nodemon node_modules/.bin/babel-node index.js

注意:我的入口文件是index.js。将其替换为您的入口文件(许多有app.js/server.js)。

JavaScript模块文件的mime类型错误

该问题的常见根源是“模块”类型JavaScript文件的mime类型不能被处理或交付这些文件的服务器、客户端或ECMAScript引擎识别为“模块”类型。

The problem is the developers of Module JavaScript files incorrectly associated Modules with a new ".mjs" (.js) extension, but then assigned it a MIME-type server type of "text/javascript". This means both .js and .mjs types are the same. In fact the new type for .js JavaScript files has also changed to "application/javascript", further confusing the issue. So Module JavaScript files are not being recognized by any of these systems, regardless of Node.js or Babel file processing systems in development.

主要的问题是，大多数服务器或客户端(现代HTML5浏览器)还不知道这种新的JavaScript“模块”子类型。换句话说，除了JavaScript类型，他们没有办法知道Module文件类型到底是什么!

你得到了你发布的响应，JavaScript引擎说它需要知道这个文件是否是Module类型的JavaScript文件。

The only solution, for server or client, is to change your server or browser to deliver a new Mime-type that trigger ES6 support of Module files, which have an .mjs extension. Right now, the only way to do that is to either create a HTTP content-type on the server of "module" for any file with a .mjs extension and change your file extension on module JavaScript files to ".mjs", or have an HTML script tag with type="module" added to any external <script> element you use that downloads your external .js JavaScript module file.

一旦你欺骗浏览器或JavaScript引擎接受新的Module文件类型，它们就会开始在你使用的JS引擎或Node.js系统中进行脚本杂技表演。

I had the same problem when I started to use Babel... But later, I had a solution... I haven't had the problem any more so far... Currently, Node.js v12.14.1, "@babel/node": "^7.8.4", I use babel-node and nodemon to execute (Node.js is fine as well..) package.json: "start": "nodemon --exec babel-node server.js "debug": "babel-node debug server.js"!! Note: server.js is my entry file, and you can use yours. launch.json. When you debug, you also need to configure your launch.json file "runtimeExecutable": "${workspaceRoot}/node_modules/.bin/babel-node"!! Note: plus runtimeExecutable into the configuration. Of course, with babel-node, you also normally need and edit another file, such as the babel.config.js/.babelrc file

如果有人在使用TypeScript时遇到了这个问题，对我来说，解决它的关键是改变

    "target": "esnext",
    "module": "esnext",

to

    "target": "esnext",
    "module": "commonjs",

在我的tsconfig.json中。我的印象是“esnext”是“最好的”，但这只是一个错误。

文档很混乱。我使用Node.js在我的计算机上执行一些本地任务。

让我们假设我的旧脚本是test.js。在里面，如果我想用的话

import something from "./mylocalECMAmodule";

它会抛出一个这样的错误:

(node:16012) Warning: To load an ES module, set "type": "module" in the package.json or use the .mjs extension.
SyntaxError: Cannot use import statement outside a module
...

这不是模块错误，而是Node.js错误。禁止加载“模块”之外的任何东西。

要解决这个问题，只需将旧脚本test.js重命名为test.mjs。

这是所有。