How to Polyfill node core modules in webpack 5

Question

webpack 5 no longer do auto-polyfilling for node core modules. How to fix it please?

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.

Answer 1

I was also getting these error's when upgrading from webpack v4 to v5. Resolved by making the following changes to webpack.config.js

added resolve.fallback property

removed node property

{
resolve: {
  modules: [...],
  fallback: {
    "fs": false,
    "tls": false,
    "net": false,
    "path": false,
    "zlib": false,
    "http": false,
    "https": false,
    "stream": false,
    "crypto": false,
    "crypto-browserify": require.resolve('crypto-browserify'), //if you want to use this module also don't forget npm i crypto-browserify 
  } 
},
entry: [...],
output: {...},
module: {
  rules: [...]
},
plugins: [...],
optimization: {
  minimizer: [...],
},
// node: {
//   fs: 'empty',
//   net: 'empty',
//   tls: 'empty'
// },
}

upgrade from v4 to v5 => https://webpack.js.org/migrate/5/#clean-up-configuration

Answer 2

Re-add support for Node.js core modules with node-polyfill-webpack-plugin:

With the package installed, add the following to your webpack.config.js:

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

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

Answer 3

I think most the answers here would resolve your issue. However, if you don't need Polyfills for your node development, then I suggest using target: 'node' in your Webpack module configuration. This helped resolve the issue for me.

Here is some documentation on the answer: https://webpack.js.org/concepts/targets/

Answer 4

As per Web3 documentation:

If you are using create-react-app version >=5 you may run into issues building. This is because NodeJS polyfills are not included in the latest version of create-react-app.

Solution:

Install react-app-rewired and the missing modules

If you are using yarn:

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

If you are using npm:

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

Create config-overrides.js in the root of your project folder with the content:

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;
}

Within package.json change the scripts field for start, build and test. Instead of react-scripts replace it with react-app-rewired before:

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

after:

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

The missing Nodejs polyfills should be included now and your app should be functional with web3.

If you want to hide the warnings created by the console:

In config-overrides.js within the override function, add:

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

Answer 5

I faced this issue with create-react-app which by default gave me

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

I fixed it by just changing react-scripts to version 4.0.3.

Answer 6

Looks like you've used the path package which is not included in webpack builds by default. For me, extending the webpack config like this helped:

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

Also install path-browserify via npm install path-browserify --save-dev or yarn add path-browserify --dev if you're using yarn.

Answer 7

You need React => v17 React scripts=> v5 webpack => v5

To Fix The Problem

1) Install

"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) Creating config-overrides.js in root directory Image

3) Add configs to config-overrides.js

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) Change packages.json

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

Problem solved :)

Answer 8

Create React App just released v5 which now implements Webpack v5. This is going to fully break many libraries which includes web3 as the required Node core library polyfills will be missing.

To resolve this quickly you can change this in your package.json:

"react-scripts": "^5.0.0"

To this

"react-scripts": "4.0.3"

After this:

rm -r node_modules

rm package-lock.json

npm install

Answer 9

It happen with me while I reinstall the node modules my webpack current version is 5.38.1, I have fixed the issue with npm i path-browserify -D after installation you have to update your webpack.config.js resolve{} with fallback: {"fs": false, "path": require.resolve("path-browserify")} while not using "fs": false it show errors i.e: Module not found: Error: Can't resolve 'fs' in '/YOUR DIRECTORY ...' so don't forget to add it; with other stuff it look like:

module.exports = {
   ...
   resolve: {
    extensions: [".js", ".jsx", ".json", ".ts", ".tsx"],// other stuff
    fallback: {
      "fs": false,
      "path": require.resolve("path-browserify")
    }
  },
};

remove node property if it exist in your webpack.config.js file

Answer 10

Method 1

• Open project/node_modules/react-scripts/config/webpack.config.js

• In fallback add "crypto": require.resolve("crypto-browserify")

resolve: {
   fallback: {
       "crypto": require.resolve("crypto-browserify")
   }
} 

• Install npm i crypto-browserify
• Restart your app.

Above method doesn't work if you commit since we aren't node_modules

Method 2

• Install patch-package: yarn add patch-package

• Install the needed pollyfills.(do an initial build of your application and it will tell you.)

• Modify node_modules/react-scripts/config/webpack.config.js. Here's an example. This is taken from Webpack's docs.

module.exports = {
  //...
  resolve: {
    fallback: {
      assert: require.resolve('assert'),
      buffer: require.resolve('buffer'),
      console: require.resolve('console-browserify'),
      constants: require.resolve('constants-browserify'),
      crypto: require.resolve('crypto-browserify'),
      domain: require.resolve('domain-browser'),
      events: require.resolve('events'),
      http: require.resolve('stream-http'),
      https: require.resolve('https-browserify'),
      os: require.resolve('os-browserify/browser'),
      path: require.resolve('path-browserify'),
      punycode: require.resolve('punycode'),
      process: require.resolve('process/browser'),
      querystring: require.resolve('querystring-es3'),
      stream: require.resolve('stream-browserify'),
      string_decoder: require.resolve('string_decoder'),
      sys: require.resolve('util'),
      timers: require.resolve('timers-browserify'),
      tty: require.resolve('tty-browserify'),
      url: require.resolve('url'),
      util: require.resolve('util'),
      vm: require.resolve('vm-browserify'),
      zlib: require.resolve('browserify-zlib'),
    },
  },
};

• Don't add all of them, add only the ones you need.

Make sure you install the packages first before modifying the webpack config.

• Run yarn patch-package react-scripts. This will generate a patch (this should be committed in your repo going forward).

• Add a postinstall script to package.json: "postinstall": "yarn patch-package". Now, anytime, someone installs npm deps on this project, will get the patch you created in step 3 applied automatically.

  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject",
    "postinstall": "yarn patch-package"
  },

Answer 11

My solution for #VUE

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'
  ]

})

Answer 12

My environment is like this:

• React => v17
• React scripts=> v5
• webpack => v5

To Fix The Problem follow the below instructions

1- Install below packages

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

2- Create config-coverrides.js in Root dir of your project next to the package.json

add the below code to it:

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- Change the packages.js like the below

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

Answer 13

npm install path-browserify and then try to change webpack configuration to include:

module.exports = {
    ...
    resolve: {
        alias: {
            path: require.resolve("path-browserify")
        }
    }
};

Answer 14

I'm using create-react-app with craco, and I encountered the following errors when upgrading to webpack 5:

'buffer'

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 }

This was resolved simply by installing the buffer package with npm install -D buffer.

'fs'

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

This was resolved by setting a webpack fallback in the craco configuration craco.config.js:

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;
        },
    },
}

Answer 15

you want to used in

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

add in webpack.config.js

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

Answer 16

This is happening with the new vue-cli upgrade (v5). In order to fix it (the empty modules way), you have to change vue.config.js this way:

configureWebpack: (config) => {
  config.resolve.fallback = {
    ...config.resolve.fallback,
    // Include here the "empty" modules
    url: false,
    util: false,
    querystring: false,
    https: false,
  };
}

Answer 17

I found a solution that worked for me:

1. npm uninstall webpack
2. delete the "package-lock.json" file
3. npm install [email protected] --force
4. include in the "package.json" file the following in your "scripts":

   "scripts": {
       "start": "SET NODE_OPTIONS=--openssl-legacy-provider && react-scripts start",
       "build": "SET NODE_OPTIONS=--openssl-legacy-provider && react-scripts build",
       "test": "react-scripts test",
       "eject": "react-scripts eject"
   }
   

Answer 18

All other answers are missing one important piece: how NOT to polyfill the node core modules. In case the error comes from some module in dependency of dependency of your dependency, which you actually do not need, you can quite safely ignore it. In that case, the most simple workaround is to add to your package.json these lines:

"browser": {
  "fs": false,
  "path": false,
  "os": false
}

And similarly for other core node modules if you need to ignore them.

This approach works great for frameworks where the actual webpack config is not directly accessible by default (like Angular).

I have found this solution when looking for a different error.

Answer 19

For those still doing configuration through react-app-rewired's config-overrides.js file, this will work:

config-overrides.js

const { override, addWebpackPlugin } = require('customize-cra')
const NodePolyfillPlugin = require("node-polyfill-webpack-plugin")

module.exports = override(addWebpackPlugin(new NodePolyfillPlugin()))

package.json

...
"dependencies": {
    ...
    "customize-cra": "^1.0.0",
    "node-polyfill-webpack-plugin": "^2.0.1"
  },

This will inject node-polyfill-webpack-plugin as a webpack 5 plugin.

Answer 20

npm install assert --save

npm install buffer --save

For anyone facing similar issue, just install the missing modules. These modules are reported as missing because they are part of node.js, but are available separately also via the npm.

Answer 21

I got this error while imported Router from express import { Router } from 'express';

Resolved after correction import { Router } from '@angular/router';

Answer 22

Faced the same issue, here's a solution:

1. Remove package-lock.json from the project folder and npm uninstall webpack
2. Downgrade react-script from 5ˆ to 4.0.3
3. Make sure package-lock.json is deleted/removed
4. Install webpack using npm install [email protected]
5. Finally, run npm install using the terminal

Answer 23

I tried this https://stackoverflow.com/a/71803628/15658978 solution and it solved the problem form me.

simply run the following 2 commands

npm uninstall react-scripts
npm install [email protected]

Answer 24

I had a React.js and Firebase app and it was giving the same error. I solved my issue by removing require('dotenv').config();. New React.js versions automatically handles loading packages like dotenv.

This polyfill error is not only with dotenv package but also with some other packages. So, if you have some loading statements as above, you can remove them and retry again.

Answer 25

My app threw the same error yesterday. I spent hours reading questions/answers here on SO and trying some. What has worked for me is this:

https://github.com/ChainSafe/web3.js#troubleshooting-and-known-issues

Answer 26

If it's Twilio you use:

The Twilio module is not intended for use in client-side JavaScript, which is why it fails for your Angular application. Twilio uses your Account SID and your Auth Token, the use in the client side represents a risk; So the best is to use it on the server side and to use the API.

Answer 27

With create-react-app v17 and scripts 5.0.0 you need to add a fallback to your webpack.config.js and install 'process'.

   `module.exports = function (webpackEnv) {
      .........
      return {
       .........
      resolve: {
      ..........
      fallback: { "process": require.resolve("process/browser") },`

Answer 28

Secret's answer very nearly worked for me (I don't have enough reputation yet to comment on there, sorry!)

After having followed the steps in their answer it then told me that because of the difference in required versions of eslint, I should add SKIP_PREFLIGHT_CHECK=true to a .env file in the project, so I just added it to my existing one.

It would then successfully build (finally!) But then I noticed, in Chrome at least, that I couldn't click on anything or even select any text. Turns out that there's still an Iframe over the top of everything that can be removed in Inspector. - This applies when running a dev build, npm run start, I am not sure if it does it on a production build.

I must say this sudden change IMO really hasn't been very well thought through!

Answer 29

if you are using create-react-app with craco then configuration in craco.config.js should be like this:

module.exports = {
  webpack: {
      configure: {
        resolve: {
          fallback: {
            "path": require.resolve("path-browserify")
          },
        },
      },
    },
}

Answer 30

If you're having this error on your react app, webpack.config.js would not help you override the webpack config. You have to use craco to solve this and then run your project with craco ie

    craco.config.js

     const path = require('path');
     module.exports = {
      webpack: {
       configure: {
        resolve: {
         fallback: {
          crypto: require.resolve('crypto-browserify'),
         },
        },
       },
      },
     };

Then you run your react app on craco ie

    package.json
 
    "scripts": {
     "start": "craco start",
     "build": "craco build",
    },