Socket.io-client没有默认导出 [英] Socket.io-client no default export

问题描述

我目前正在研究聚合物3中的一个项目，其中一个组件需要导入socket.io-client，但无论我尝试什么，我都无法让它工作。

I'm currently working on a project in polymer 3, one of the components needs to import socket.io-client but whatever i try i can't get it to work.

我试过：

import io from 'socket.io-client';

我得到的回报：

未捕获的SyntaxError：请求的模块
'../../node_modules/socket.io-client/lib/index.js'不提供名为'default'的
导出

Uncaught SyntaxError: The requested module '../../node_modules/socket.io-client/lib/index.js' does not provide an export named 'default'

与此相同：

import io from 'socket.io-client/dist/socket.io.js';

我得到的回报：

Uncaught SyntaxError：请求的模块
'../../node_modules/socket.io-client/dist/socket.io.js'没有
提供名为'的导出默认'

Uncaught SyntaxError: The requested module '../../node_modules/socket.io-client/dist/socket.io.js' does not provide an export named 'default'

我也试过这个：

import * as io from 'socket.io-client'

我得到的回报：

ReferenceError：在index.js中未定义require：4

ReferenceError: require is not defined at index.js:4

这个：

import * as io from 'socket.io-client/dist/socket.io.js'

我得到的回报：

TypeError：无法读取未定义的属性'Buffer'

TypeError: Cannot read property 'Buffer' of undefined

我后来看过了来自socket.io-client的代码，实际上似乎没有在代码中使用任何es6导出，这可以解释为什么它我ndeed不起作用。

I later on looked trough the code from socket.io-client and there really don't appear to be any es6 exports used in the code, that would explain why it indeed doesn't work.

我觉得奇怪的是，导入语法甚至在他们的网站上列为支持。我假设我可能使用了错误的构建或其他东西，但我不知道为什么会这样，因为我使用socket.io-client：^ 2.1.1如果有人知道我做错了什么我会很高兴听到。

What i find weird tho is that the import syntax is even listed on their site as supported. I assume i may be using a wrong build or something but i don't know why that would be true as i use "socket.io-client": "^2.1.1" if anyone knows what i'm doing wrong i'd be happy to hear.

推荐答案

聚合物需要使用ES模块 - 因为socket.io-client无法在package.json中安装模块（ https：/ /github.com/rollup/rollup/wiki/pkg.module ），Polymer必须依赖于使用ES模块编写的源。 Socket.io-client既不提供。因此，您只能在index.html或其中一个模板中导入它或使用其他库（或者使用webpack / gulp做一些疯狂的事情）......

Polymer requires the use of ES modules - since socket.io-client fails to have module in package.json (https://github.com/rollup/rollup/wiki/pkg.module), Polymer must rely on a source which is written with ES modules. Socket.io-client provides neither. So you could only import it in index.html or one of your templates or use another library (or do some crazy thing with webpack / gulp)...

index。 html

index.html

<script src="node_modules/socket.io-client/dist/socket.io.js"></script>

我在webcomponents导入后导入了它。

I have imported it after webcomponents import.

在一个组件中：

const socket = io(...);

有效。

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