我的环境是这样的:

React => v17 React脚本=> v5 Webpack => v5

要解决这个问题，请遵循下面的说明

1-安装以下软件包

yarn add fs assert https-browserify os os-browserify stream-browserify stream-http react-app-rewired

2-在项目根目录下package.json旁边创建config-coverrides.js

添加以下代码:

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-像下面这样修改packages.js

"脚本":{ “start”:“react-app-rewired start”， “build”:“react-app-rewired build”， “test”:“react-app-rewired test” "eject": "react-app-rewired eject" }，

使用node-polyfill-webpack-plugin重新添加对Node.js核心模块的支持:

安装包后，将以下内容添加到webpack.config.js中:

const NodePolyfillPlugin = require("node-polyfill-webpack-plugin")

module.exports = {
    // Other rules...
    plugins: [
        new NodePolyfillPlugin()
    ]
}

看起来你已经使用了默认情况下不包含在webpack构建中的path包。对我来说，像这样扩展webpack配置有帮助:

{
  // rest of the webpack config
  resolve: {
    // ... rest of the resolve config
    fallback: {
      "path": require.resolve("path-browserify")
    }
  },
}

也可以通过npm install path-browserify——save-dev或yarn添加path-browserify——dev来安装path-browserify。

根据Web3文档:

如果你使用的是create-react-app版本>=5，你可能会遇到构建问题。这是因为最新版本的create-react-app中没有包含NodeJS的polyfills。

解决方案:

安装react-app-rewired和缺少的模块

如果你用的是纱线:

yarn add --dev react-app-rewired crypto-browserify stream-browserify assert stream-http https-browserify os-browserify url buffer process

如果你正在使用npm:

npm install --save-dev react-app-rewired crypto-browserify stream-browserify assert stream-http https-browserify os-browserify url buffer process

在项目文件夹的根目录下创建config-override .js，内容如下:

const webpack = require('webpack');

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

内包。Json改变脚本字段启动，构建和测试。用react-app-rewired代替react-scripts 之前:

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

后:

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

缺少的Nodejs polyfills现在应该包括在内，你的应用程序应该可以使用web3。

如果你想隐藏控制台创建的警告:

在config-override .js的override函数中，添加:

config.ignoreWarnings = [/Failed to parse source map/];

Compiled with problems:X

ERROR in ./node_modules/body-parser/lib/read.js 24:11-26

Module not found: Error: Can't resolve 'zlib' in 'E:\My Documents\work\web\mbamasala\node_modules\body-parser\lib'

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


ERROR in ./node_modules/body-parser/lib/types/urlencoded.js 217:12-34

Module not found: Error: Can't resolve 'querystring' in 'E:\My Documents\work\web\mbamasala\node_modules\body-parser\lib\types'

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: { "querystring": require.resolve("querystring-es3") }'
    - install 'querystring-es3'
If you don't want to include a polyfill, you can use an empty module like this:
    resolve.fallback: { "querystring": false }


ERROR in ./node_modules/destroy/index.js 15:17-41

Module not found: Error: Can't resolve 'fs' in 'E:\My Documents\work\web\mbamasala\node_modules\destroy'


ERROR in ./node_modules/destroy/index.js 17:13-30

Module not found: Error: Can't resolve 'stream' in 'E:\My Documents\work\web\mbamasala\node_modules\destroy'

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


ERROR in ./node_modules/destroy/index.js 19:11-26

Module not found: Error: Can't resolve 'zlib' in 'E:\My Documents\work\web\mbamasala\node_modules\destroy'

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


ERROR in ./node_modules/mime-types/index.js 15:14-37

Module not found: Error: Can't resolve 'path' in 'E:\My Documents\work\web\mbamasala\node_modules\mime-types'

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


ERROR in ./node_modules/safer-buffer/safer.js 4:13-30

Module not found: Error: Can't resolve 'buffer' in 'E:\My Documents\work\web\mbamasala\node_modules\safer-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 }


ERROR in ./node_modules/string_decoder/node_modules/safe-buffer/index.js 4:13-30

Module not found: Error: Can't resolve 'buffer' in 'E:\My Documents\work\web\mbamasala\node_modules\string_decoder\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 }

我试了很多办法，但都没有解决。 在手动搜索后，我得到了一行代码，它自动插入到我的vs code中 从body-parser导入{json} 我移开了，节省了时间。 我希望它能帮助到一些人。 谢谢。

我的问题是，我试图使用JSON。解析，然后当我开始写，自动完成显示我json(注意小字母)，尽管我重命名为json。当我按回车键时，它自动导入 (import {json} from "express/lib/response";) 这是原因，我根本没有注意到，在后来的开发过程中，我的应用程序非常糟糕，我花了大约6个小时才注意到这一点，因为应用程序相当大。

所以如果上面的解决方案都不起作用，看看你是否没有导入一些东西。