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/];

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。

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/

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()
    ]
}

我的VUE解决方案

const { defineConfig } = require('@vue/cli-service')
const webpack = require('webpack');
module.exports = defineConfig({
  configureWebpack: {
    plugins: [
      new webpack.ProvidePlugin({
        Buffer: ['buffer', 'Buffer'],
      }),
      new webpack.ProvidePlugin({
          process: 'process/browser',
      })
    ],
    resolve: {
      fallback: {
        "os": require.resolve("os-browserify/browser"),
        "url": require.resolve("url/"),
        "crypto": require.resolve("crypto-browserify"),
        "https": require.resolve("https-browserify"),
        "http": require.resolve("stream-http"),
        "assert": require.resolve("assert/"),
        "stream": require.resolve("stream-browserify"),
        "buffer": require.resolve("buffer")
      }
    }
  },

  transpileDependencies: [
    'vuetify'
  ]

})

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;
        },
    },
}