How to use the natural.LogisticRegressionClassifier function in natural

for (let item of data) {
        const {text} = item;
        const tokens = tokenizer(text.trim());
        words = words.concat(tokens);
      }

      examples[key].validate.push(words);

      j++;
    }
  }
}

// console.log('examples', JSON.stringify(examples, null, 4));

const classifier = new natural.LogisticRegressionClassifier();

// do training
for (let key in examples) {
  const data = examples[key];
  const {train} = data;

  for (let words of train) {
    classifier.addDocument(words, key);
  }
}

function evaluate(trainType) {
  console.log('done train');

  let correct = 0;
  let total = 0;

var natural = require('natural');
var fs = require('fs');
var classifier = new natural.LogisticRegressionClassifier();

fs.readFile('training_data.json', 'utf-8', function(err, data){
    if (err){
        console.log(err);
    } else {
        var trainingData = JSON.parse(data);
        train(trainingData);
    }
});

function train(trainingData){
    console.log("Training");
    trainingData.forEach(function(item){
        classifier.addDocument(item.text, item.label);
    });
    var startTime = new Date();

const evaluate = require('../evaluate');
const natural = require('natural');
const path = require('path');

evaluate(new natural.LogisticRegressionClassifier(), {learn: 'addDocument', train: 'train', classify: 'classify'}, path.join(__dirname, 'evaluate.json'));