natural: log4js causing issues with client-side usage

I’m trying to use natural on the client side and I’m getting errors on (Webpack) compilation like the following:

Error in ./~/log4js/lib/appenders/clustered.js
Module not found: 'cluster' in /Users/liadrian/Dev/naive-bayes/node_modules/log4js/lib/appenders

 @ ./~/log4js/lib/appenders/clustered.js 3:14-32

Error in ./~/log4js/lib/appenders/gelf.js
Module not found: 'dgram' in /Users/liadrian/Dev/naive-bayes/node_modules/log4js/lib/appenders

 @ ./~/log4js/lib/appenders/gelf.js 5:12-28

Error in ./~/log4js/lib/appenders/hipchat.js
Module not found: 'hipchat-notifier' in /Users/liadrian/Dev/naive-bayes/node_modules/log4js/lib/appenders

... and many more like the above

The problem

This is caused by a dependency on log4js, which for some reason has a lot of require statements in its appenders that are not declared in its own package.json file.

An example:

// node_modules/log4js/lib/appenders/clustered.js
var cluster = require('cluster');

But package.json from the log4js module does not include cluster as a dependency. As a result, when Webpack is trying to compile my app, an error is thrown for each of these delinquent requires (i.e. require statements for modules not listed in its package.json dependency list).

The bottom line is: log4js is the problem.

The solution

After looking into this, I was able to find that log4js is only used within the Brill POS Tagger module. I recommend that we move away from log4js completely and replace those logging statements with normal console.log or console.warn statements instead.

I have already attempted to do this, and can confirm that this will indeed solve the problem.

I will submit a PR if the community agrees it is beneficial to the project.