simple-sentiment-lib/analysis/sentiment.js

Very compact and simple to use sentiment analysis lib

const afinnJson = require("../lists/afinn.json");

// tokenize input string and replace characters with regex
const tokenizeInput = (input) => {
  return input
    .toLowerCase()
    .replace(/\n/g, " ")
    .replace(/[.,\/#!?$%\^&\*;:{}=_`\"~()]/g, " ")
    .replace(/\s\s+/g, " ")
    .trim()
    .split(" ");
};

// Bereken de negatieve waarde adhv. tokens uit afinn wordlist
const calcNegative = (input) => {
  var addToken = (token, score) => {
    hits -= score;
    words.push(token);
  };

  var tokens = tokenizeInput(input),
    hits = 0,
    words = [];

  tokens.forEach((token) => {
    if (afinnJson.hasOwnProperty(token)) {
      if (afinnJson[token] < 0) {
        addToken(token, afinnJson[token]);
      }
    }
  });

  return {
    score: hits,
    comparative: hits / tokens.length,
    words: words,
  };
}

// Bereken de positieve waarde adhv. tokens uit afinn wordlist
const calcPositive = (input) => {
  var addToken = (token, score) => {
    hits += score;
    words.push(token);
  };

  var tokens = tokenizeInput(input),
    hits = 0,
    words = [];

  tokens.forEach((token) => {
    if (afinnJson.hasOwnProperty(token)) {
      if (afinnJson[token] > 0) {
        addToken(token, afinnJson[token]);
      }
    }
  });

  return {
    score: hits,
    comparative: hits / tokens.length,
    words: words,
  };
};

const sent_analysis = (input) => {
  var negative = calcNegative(input);
  var positive = calcPositive(input);

  return {
    score: positive.score - negative.score,
    comparative: positive.comparative - negative.comparative,
    positive,
    negative,
  };
};

module.exports = sent_analysis;