Reduce the size of the npm package by limiting the included files

Nobody has claimed this yet.

Looks like the `files` property (https://docs.npmjs.com/files/package.json#files) is not used in `package.json` to specify the included files, nor is the `.npmignore` file (https://docs.npmjs.com/misc/developers#keeping-files-out-of-your-package) is being used for blacklisting unwanted files, for the package published to npm.

Would you consider adding either the `files` property or the `.npmignore` file, so that the resulting package file would have smaller size?

The current size can be seen when executing the command `npm pack` (https://docs.npmjs.com/cli/pack).

> This issue was create via [tawata](https://github.com/paazmaya/tawata/)

Inspect package.json and the possible .npmignore configuration, then run npm pack to review which files are included and measure the package size. Done means the published package excludes unnecessary files and the resulting npm pack archive is smaller without removing required package contents.

Written by the indexing model from the issue text.