导入ECMAScript 6时“Uncaught SyntaxError: Cannot use import statement outside a module”

我正在使用ArcGIS JSAPI 4.12，希望使用空间幻象在地图上绘制军事符号。

当我将milsymbol.js添加到脚本中时，控制台返回错误

无法在模块外部使用import语句

所以我添加type="module"到脚本中，然后它返回

Uncaught ReferenceError: ms未定义

这是我的代码:

<link rel="stylesheet" href="https://js.arcgis.com/4.12/esri/css/main.css">
<script src="https://js.arcgis.com/4.12/"></script>
<script type="module" src="milsymbol-2.0.0/src/milsymbol.js"></script>

<script>
    require([
        "esri/Map",
        "esri/views/MapView",
        "esri/layers/MapImageLayer",
        "esri/layers/FeatureLayer"
    ], function (Map, MapView, MapImageLayer, FeatureLayer) {

        var symbol = new ms.Symbol("SFG-UCI----D", { size: 30 }).asCanvas(3);
        var map = new Map({
            basemap: "topo-vector"
        });

        var view = new MapView({
            container: "viewDiv",
            map: map,
            center: [121, 23],
            zoom: 7
        });
    });
</script>

所以，无论我是否添加type="module"，总会有错误。但是在Spatial Illusions的官方文档中，脚本中没有type="module"。我现在真的很困惑。他们如何在不添加类型的情况下让它工作呢?

文件milsymbol.js

import { ms } from "./ms.js";

import Symbol from "./ms/symbol.js";
ms.Symbol = Symbol;

export { ms };

当前回答

当它在Babel转译中失败时发生此错误。

2021-11-10 08:57:45

其他回答

错误的原因如下:

You're currently loading the source file in the src directory instead of the built file in the dist directory (you can see what the intended distributed file is here). This means that you're using the native source code in an unaltered/unbundled state, leading to the following error: Uncaught SyntaxError: Cannot use import statement outside a module. This should be fixed by using the bundled version since the package is using rollup to create a bundle. The reason you're getting the Uncaught ReferenceError: ms is not defined error is because modules are scoped, and since you're loading the library using native modules, ms is not in the global scope and is therefore not accessible in the following script tag.

看起来你应该能够加载这个文件的dist版本，在窗口上定义ms。请查看库作者提供的这个示例，以了解如何做到这一点。

2019-10-03 04:31:03

我想我应该加上这句话，因为这对我来说并不明显。您需要将type="module"添加到所有脚本包含，而不仅仅是您想用于实用程序文件的脚本包含。

index . html:

<script type="module" src="js/controllers/utils.js"></script>
<script type="module" src="js/controllers/main.js"></script>`

main.js:

import myFunction from './utils.js

utils.js:

export default myFunction

2022-10-17 21:24:59

我在React中得到了这个错误，并通过以下步骤修复了它:

进入项目根目录，打开Package。Json文件进行编辑。添加“类型”:“模块”; 保存并重新启动服务器。

2021-01-04 10:24:21

我得到了这个错误，因为我忘记了脚本标签中的type="module":

<script type="module" src="milsymbol-2.0.0/src/milsymbol.js"></script>

2019-11-03 10:43:50

如果您想对模块使用import而不是require()，请更改或添加package中的type值到module。json文件

例子:

包中。json文件

{
  "name": "appsample",
  "version": "1.0.0",
  "type": "module",
  "description": "Learning Node",
  "main": "app.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Chikeluba Anusionwu",
  "license": "ISC"
}

import http from 'http';

var host = '127.0.0.1',
    port = 1992,
    server = http.createServer();

server.on('request', (req, res) => {
  res.writeHead(200, {"Content-Type": "text/plain"});
  res.end("I am using type module in package.json file in this application.");
});

server.listen(port, () => console.log(
    'Listening to server ${port}. Connection has been established.'));

2021-09-09 16:28:48

导入ECMAScript 6时“Uncaught SyntaxError: Cannot use import statement outside a module”

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