For translation of article "Natural language processing for Node.js" - https://bit.ly/2QZsts1

classification-index.js

// index.js

var natural = require('natural');

var classifier = new natural.BayesClassifier();
classifier.addDocument('i am long qqqq', 'buy');
classifier.addDocument('buy the q\'s', 'buy');
classifier.addDocument('short gold', 'sell');
classifier.addDocument('sell gold', 'sell');
classifier.train();

console.log(classifier.classify('i am short silver'));
console.log(classifier.classify('i am long copper'));