React build - not found: Error: Can't resolve 'buffer'

Question

I am having an error when I build my application in react. I noticed this error only when I tried to build application.

When I stopped dev server and ran it again, it showed the same error. It seems that I made some change that only showed when I started the server again or make build:

Module not found: Error: Can't resolve 'buffer' in '\node_modules\htmlparser2\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 these module and configure a polyfill for it.

If you want to include a polyfill, you need to install 'buffer'. If you don't want to include a polyfill, you can use an empty module like this: resolve.alias: { "buffer": false }

error Command failed with exit code 1.

My application is made in CRA and Typescript. This is my package.json:

{
  "name": "my-app",
  "version": "0.1.0",
  "private": true,
  "scripts": {
    "start": "react-scripts start",
    "build": "cross-env NODE_OPTIONS='--max-old-space-size=4096' react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "dependencies": {
    "@apollo/react-hooks": "^4.0.0",
    "@date-io/moment": "^1.3.13",
    "@material-ui/core": "^4.11.0",
    "@material-ui/icons": "^4.9.1",
    "@material-ui/lab": "^4.0.0-alpha.56",
    "@material-ui/pickers": "^3.2.10",
    "@optimizely/react-sdk": "^2.4.0",
    "apollo-boost": "^0.4.9",
    "classnames": "^2.2.6",
    "formik": "^2.2.5",
    "graphql": "^15.4.0",
    "lodash": "^4.17.20",
    "moment": "^2.29.1",
    "react": "^16.13.1",
    "react-app-polyfill": "^2.0.0",
    "react-dom": "^16.13.1",
    "react-google-recaptcha": "^2.1.0",
    "react-masonry-css": "^1.0.14",
    "react-router-dom": "^5.2.0",
    "react-test-renderer": "^16.13.1",
    "react-toastify": "^6.1.0",
    "reset-css": "^5.0.1",
    "use-debounce": "^5.1.0"
  },
  "devDependencies": {
    "@testing-library/jest-dom": "^5.11.6",
    "@testing-library/react": "^11.2.1",
    "@testing-library/user-event": "^12.2.2",
    "@types/classnames": "^2.2.11",
    "@types/enzyme": "^3.10.8",
    "@types/enzyme-adapter-react-16": "^1.0.6",
    "@types/jest": "^26.0.15",
    "@types/lodash": "^4.14.165",
    "@types/moment": "^2.13.0",
    "@types/node": "^14.14.9",
    "@types/react": "^16.9.56",
    "@types/react-dom": "^16.9.9",
    "@types/react-google-recaptcha": "^2.1.0",
    "@types/react-router-dom": "^5.1.6",
    "cross-env": "^7.0.2",
    "enzyme": "^3.11.0",
    "enzyme-adapter-react-16": "^1.15.5",
    "enzyme-to-json": "^3.6.1",
    "husky": "^4.3.0",
    "jest-dom": "^4.0.0",
    "jest-sonar-reporter": "^2.0.0",
    "lint-staged": "^10.5.1",
    "node-sass": "^5.0.0",
    "prettier": "^2.2.0",
    "ts-jest": "^26.4.4",
    "typescript": "^4.1.2"
  }
}

Answer 1

You need to install the buffer package

npm install buffer

Answer 2

You have to Install this

npm install assert browserify-zlib buffer process stream-browserify util .

it will help you out

Answer 3

I found a solution to my problem. It is a bit weird that it didn't show up as test error.

SOLUTION

To solve this I just replaced location of TEST_ID to be in my component, and that my-component.test file to import it from there:

My component

import React, { FunctionComponent } from 'react';

/* Tests */
export const TEST_ID = 'my-component-test-id';

export const MyComponent: FunctionComponent = () => {
  return <div data-test-id={TEST_ID}>123</div>;
};

Test

import React from 'react';
import { cleanup } from '@testing-library/react';
import { mount } from 'enzyme';

import { TEST_ID } from './my-component';

import MyComponent from './my-component'

afterEach(cleanup);

it('Render My component and have some value', () => {
  const wrapper = mount(<MyComponent />);

  const myComponent = wrapper.find(`[data-testid='${TEST_ID}']`);

  expect(myComponent).toHaveValue('some value');
});

Analysis

Apparently if you import some value (in my case a constant) from .test file, if you try and build your app, the mentioned error will show up.

In my case I had a component:

MyComponent

import React, { FunctionComponent } from 'react';

/* Tests */
import { TEST_ID } from './test/my-component.test';

export const MyComponent: FunctionComponent = () => {
  return <div data-test-id={TEST_ID}>some value</div>;
};

The TEST_ID was imported from my-component.test file. The purpose of that constant was to have that test id set for component so I can find that element based of that test id in my test.

Test

import React from 'react';
import { cleanup } from '@testing-library/react';
import { mount } from 'enzyme';

import MyComponent from './my-component'

afterEach(cleanup);

export const TEST_ID = 'my-component-test-id';

it('Render My component and have some value', () => {
  const wrapper = mount(<MyComponent />);

  const myComponent = wrapper.find(`[data-testid='${TEST_ID}']`);

  expect(myComponent).toHaveValue('some value');
});

Answer 4

you need to install 'buffer' : npm install buffer oR npm install buffer --f