我在create-react-app中遇到了这个问题

"react": "^17.0.2",
"react-dom": "^17.0.2",
"react-scripts": "5.0.0",
"web-vitals": "^2.1.2"

我通过将react-scripts更改为4.0.3版本来解决这个问题。

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/];

对于我(使用React => v17;React脚本=> v5;webpack => v5)，由@Letton和@Richie Bendall建议的解决方案组合与另一个附加，即包一起工作。Json中，必须添加并安装以下包。还请注意fs版本“^2.0.0”抛出一个错误，因此更改为“0.0.1-security”。

"assert": "^2.0.0", 
"https-browserify": "^1.0.0", 
"os": "^0.1.2",
"os-browserify": "^0.3.0",
"react-app-rewired": "^2.1.9",
"stream-browserify": "^3.0.0",
"stream-http": "^3.2.0",
"fs":"^0.0.1-security",
"crypto-browserify": "3.12.0",
"buffer":"^6.0.3",
"node-polyfill-webpack-plugin": "^2.0.1"

安装完这些后，执行剩下的步骤，即将config-override .js添加到根目录，并更改包中的脚本内容。从react-scripts到react-app-rewired的Json修复了这个问题。

你想用在

const nodeExternals = require('webpack-node-externals');

在webpack.config.js中添加

target: "node",
devtool: "source-map",
externals: [nodeExternals()],

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/