feat - Allow overlay to be enabled for warnings (#789)

[bebraw]

What kind of change does this PR introduce?

Feature.

Did you add or update the examples/?

Yes.

Summary

Now you can use

{
  overlay: {
    errors: true,
    warnings: true
  }
}

Closes #789.

Does this PR introduce a breaking change?

No.

[SpaceK33z]

Could you document how to trigger a warning here? This text only tells me how to trigger an error. Would be handy for testing, since I can't come up with something that triggers a warning out the top of my head right now :).

[bebraw]

Yeah, the problem is, how to trigger a warning.

I tried copying

// This results in a warning:
// if(!window) require("./" + window + "parseable.js");

to the example from modus-inline, but that doesn't trigger a warning at all (not there either). Maybe something changed between webpack 1 and 2?

[SpaceK33z]

Jup, in webpack 1 that triggered a warning but in webpack 2 not anymore :'). Looking at webpack's source code on warnings.push, I found that it should trigger a warning when incorrectly cased modules are used. So perhaps add a file caseSensitive.js and import it with casesensitive.js?

[bebraw]

The problem is that those two files resolve fine on macOS. It would fail only on Windows and so on.

[SpaceK33z]

Yes, but isn't the purpose of the CaseSensitiveModulesWarning plugin to give a warning for that, exactly because it works on macOS but not on Linux/Windows? (I seriously don't know btw, I only looked at the code very quickly 😄 )

[bebraw]

The only obvious way I can see would be to go through eslint and eslint-loader. That would work regardless of the platform.

[bebraw]

Ah, yeah. I see now. I think I have to add the plugin to the configuration as it's not enabled by default.

[bebraw]

Got it. You have to do

require("./casesensitive.js");
require("./caseSensitive.js");

It requires multiple, different imports pointing to the same place in order to work. This is enough for me. 👍

[bebraw]

Done.