How to watch certain node_modules changes with webpack-dev-server

You can config in in webpack.config file or in WebpackDevServer option, to watch for changes also in node_modules (i think that by default webpack watching for changes in all files)

https://webpack.js.org/configuration/watch/#watchoptions-ignored

in the following example webpack ignored all changes in node_modules folder except specific module.

watchOptions: {
  ignored: [
    /node_modules([\\]+|\/)+(?!some_npm_module_name)/, 
    /\some_npm_module_name([\\]+|\/)node_modules/
  ]
}

ignored[0] = Regex to ignore all node_modules that not started with some_npm_module_name

ignored[1] = Regex to ignore all node_modules inside some_npm_module_name

You may also used this link npm linked modules don’t find their dependencies