Provide way to exclude files for next webpack loaders

[Ekenorg]

Next.js doesn't currently provide a way to configure webpack build loaders used by Next build. When using big externally built bundles, the build times become much longer than they should.
Here's an example: https://github.com/Ekenorg/nextdemo

Here are two ways I could find to work around this:
Using a webpack pitch loader prevents other loaders from being applied, for example expose-loader.

config.module.rules.push(
	{ test: /bundlename.js/, loader: 'expose-loader?Bundlename' }
)

This requires using a global variable though.

Another was to use a hack in next.config.js webpack section:

config.module.rules.forEach(function(rule) {
  if (!(rule.exclude instanceof Array) && typeof rule.exclude != "undefined") {
  	rule.exclude = [rule.exclude]
  }
  rule.exclude = rule.exclude || []
  rule.exclude.push(path.resolve(__dirname, "path to be excluded"))
})

In the example using either of these ways reduces the page build time from than +30 seconds to couple of seconds.

This could be fixed by adding an exclude section support to next.config.js file or by providing an config.modules.rule example in the documentation.

[arunoda]

In the example using either of these ways reduces the page build time from than +30 seconds to couple of seconds.

Actually. This is something awesome.
I'd like to invest a bit on this.

[timneutkens]

Going to close this as webpack is now used in a universal way so excluding works on server/client.