Could not resolve dependency: npm ERR! peer webpack@"^4.0.0" from [email protected]

Question

Here is details of my error: My node version is 16.13.0 and npm is 8.12.1.

PS D:\ShowCase> npm install
npm ERR! code ERESOLVE
npm ERR! ERESOLVE could not resolve
npm ERR!
npm ERR! While resolving: [email protected]
npm ERR! Found: [email protected]
npm ERR! node_modules/webpack
npm ERR!   dev webpack@"^5.47.1" from the root project
npm ERR!   peer webpack@"4.x.x || 5.x.x" from @webpack-cli/[email protected]
npm ERR!   node_modules/@webpack-cli/configtest
npm ERR!     @webpack-cli/configtest@"^1.0.4" from [email protected]
npm ERR!     node_modules/webpack-cli
npm ERR!       dev webpack-cli@"^4.7.2" from the root project
npm ERR!       3 more (@webpack-cli/configtest, @webpack-cli/info, @webpack-cli/serve)
npm ERR!   8 more (babel-loader, css-loader, ...)
npm ERR!
npm ERR! Could not resolve dependency:
npm ERR! peer webpack@"^4.0.0" from [email protected]
npm ERR! node_modules/uglifyjs-webpack-plugin
npm ERR!   dev uglifyjs-webpack-plugin@"^2.2.0" from the root project
npm ERR!
npm ERR! Conflicting peer dependency: [email protected]
npm ERR! node_modules/webpack
npm ERR!   peer webpack@"^4.0.0" from [email protected]
npm ERR!   node_modules/uglifyjs-webpack-plugin
npm ERR!     dev uglifyjs-webpack-plugin@"^2.2.0" from the root project
npm ERR!
npm ERR! Fix the upstream dependency conflict, or retry
npm ERR! this command with --force, or --legacy-peer-deps
npm ERR! to accept an incorrect (and potentially broken) dependency resolution.

Please let me know if anyone has faced the same problem. Thanks in advance.

Answer 1

The uglifyjs-webpack-plugin will work fine with Webpack 4 but will not work with Webpack 5. Since this plugin is not scheduled for Webpack 5, You better downgrade Webpack from 5 to 4. Or Try other plugins like babel-minify-webpack-plugin or terser-webpack-plugin to minify javascript if you want to use uglifyjs-webpack-plugin specifically to minimize javascript code.

---

You can check the last stable release of uglifyjs-webpack-plugin was 3 years ago, and no documented development support for Webpack 5.

Answer 2

I had a similar issue. Tried updating webpack and even installed yarn but it didn't seem to work, furthermore when I tried installing a new version of webpack-cli it threw a similar error. What I did was changing the version of webpack-cli manually on the package.json to the latest today (5.1.4) and I could finally install and run everyting else.