我正在使用craco的create-react-app，在升级到webpack 5时遇到了以下错误:

“缓冲”

Module not found: Error: Can't resolve 'buffer' in '/Users/therightstuff/my-project/node_modules/safe-buffer'

BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default.
This is no longer the case. Verify if you need this module and configure a polyfill for it.

If you want to include a polyfill, you need to:
    - add a fallback 'resolve.fallback: { "buffer": require.resolve("buffer/") }'
    - install 'buffer'
If you don't want to include a polyfill, you can use an empty module like this:
    resolve.fallback: { "buffer": false }

这个问题通过安装npm install -D buffer来解决。

'fs'

Module not found: Error: Can't resolve 'fs' in '/Users/therightstuff/my-project/node_modules/line-navigator'

这个问题通过在craco配置craco.config.js中设置webpack回退来解决:

module.exports = {
    style: {
        postcssOptions: {
            plugins: [
            require('tailwindcss'),
            require('autoprefixer'),
            ],
        },
    },
    webpack: {
        configure: (webpackConfig, { env, paths }) => {
            // eslint-disable-next-line no-param-reassign
            webpackConfig.resolve.fallback = {
                fs: false,
            };
            return webpackConfig;
        },
    },
}

我想这里的大部分答案都能解决你的问题。然而，如果你的节点开发不需要Polyfills，那么我建议在Webpack模块配置中使用target: 'node'。这帮我解决了这个问题。

这里有一些关于答案的文档:https://webpack.js.org/concepts/targets/

npm install assert --save

npm install buffer --save

对于任何面临类似问题的人，只需安装缺少的模块。这些模块被报告为缺失，因为它们是node.js的一部分，但也可以通过npm单独使用。

我喜欢把事情简单化，在这里之前不需要运行npm run-script eject，所以我降级回react-scripts@4.0.3而不是5.0.0 到目前为止，Webpack仍然没有解决这个问题

可悲的是，因为这包括一堆退役的包裹。

你需要React => v17 React脚本=> v5 webpack => v5

解决问题

1)安装

"fs": "^2.0.0",  // npm i fs
"assert": "^2.0.0",  // npm i assert
"https-browserify": "^1.0.0", // npm i https-browserify
"os": "^0.1.2", // npm i os
"os-browserify": "^0.3.0", // npm i os-browserify
"react-app-rewired": "^2.1.9", //npm i react-app-rewired
"stream-browserify": "^3.0.0", // stream-browserify
"stream-http": "^3.2.0", //stream-http

2)在根目录下创建config-override .js 图像

3)在config-override .js中添加配置

const webpack = require('webpack');
module.exports = function override(config, env) {
    config.resolve.fallback = {
        url: require.resolve('url'),
        fs: require.resolve('fs'),
        assert: require.resolve('assert'),
        crypto: require.resolve('crypto-browserify'),
        http: require.resolve('stream-http'),
        https: require.resolve('https-browserify'),
        os: require.resolve('os-browserify/browser'),
        buffer: require.resolve('buffer'),
        stream: require.resolve('stream-browserify'),
    };
    config.plugins.push(
        new webpack.ProvidePlugin({
            process: 'process/browser',
            Buffer: ['buffer', 'Buffer'],
        }),
    );

    return config;
}

3)更改packages.json

"scripts": {
  "start": "react-app-rewired start",
  "build": "react-app-rewired build",
  "test": "react-app-rewired test",
  "eject": "react-app-rewired eject"
}

问题解决了:)

我从express导入路由器时得到这个错误 import {Router} from 'express';

修正后解决 import {Router} from '@angular/ Router ';