There can be an error, "Uncaught Error: ENOENT: no such file or directory, open '...'" when using npm libraries which use "__dirname" in their source code. The problem seems to be related the context of the module path. If the entry module is located at sub directory such as 'app' or 'components', it happens. The solution is to put entry module at the root directory.
artilla's personal blog. Sorry for broken English, just in practice