ab-node-summarizer/src/SummarizerManager.js

Text summarizer using Node.js

const Summarizer = require('./Summarizer').Summarizer;

class SummarizerManager {
  constructor(string, number_of_sentences) {
    this.string = string;
    this.number_of_sentences = number_of_sentences;
    this.rank_summary = "";
    this.frequency_summary = "";
  }

  getSentiment() {
    let self = this;
    let Analyzer = require('natural').SentimentAnalyzer;
    let stemmer = require('natural').PorterStemmer;
    let analyzer = new Analyzer("English", stemmer, "afinn");
    return analyzer.getSentiment(self.string.split(" "));

  }

  getFrequencyReduction() {
    if (this.frequency_summary == "") {
      this.frequency_summary = this.getSummaryByFrequency().summary;
    }
    let dec = 1 - (this.frequency_summary.length / this.string.length);
    let string_dec = String(dec);
    return {
      reduction: string_dec.slice(2, 4) + "." + string_dec.slice(4, 5) + "%",
      summary: this.frequency_summary
    };
  }

  async getRankReduction() {
    if (this.rank_summary == "") {
      await this.getSummaryByRank();
    }
    let dec = 1 - (this.rank_summary.length / this.string.length);
    let string_dec = String(dec);
    return {
      reduction: string_dec.slice(2, 4) + "." + string_dec.slice(4, 5) + "%",
      summary: this.rank_summary
    }

  }

  async getRankReductionAsDec() {
    if (this.rank_summary == "") {
      await this.getSummaryByRank();
    }
    let dec = 1 - (this.rank_summary.length / this.string.length);
    return {
      dec_reduction: dec,
      summary: this.rank_summary
    }
  }

  getFrequencyReductionAsDec() {
    if (this.frequency_summary == "") {
      this.frequency_summary = this.getSummaryByFrequency().summary;
    }
    let dec = 1 - (this.frequency_summary.length / this.string.length);
    return {
      dec_reduction: dec,
      summary: this.frequency_summary
    }
  }

  getSummaryByFrequency() {
    try {
      let summarizer = new Summarizer(this.string, this.number_of_sentences);
      const summary_obj = summarizer.summarizeByFrequency();
      this.frequency_summary = summary_obj.summary;
      if (summary_obj.summary == '') {
        summary_obj.summary = Error("Not Enough similarities to be summarized, or the sentence is invalid."),
          summary_obj.sentence_list = Error("Not enough similarities to be summarized, or the sentence is invalid.")
      }
      return summary_obj;
    } catch (err) {
      return Error("An invalid sentence was entered");
    }

  }

  async getSummaryByRank() {
    try {
      let summarizer = new Summarizer(this.string, this.number_of_sentences);
      const summary_obj = await summarizer.summarizeByRank();
      if (typeof (summary_obj.summary) === 'undefined' || summary_obj.summary == '') {
        summary_obj.summary = Error("Not Enough similarities to be summarized, or the sentence is invalid."),
          summary_obj.sentence_list = Error("Not enough similarities to be summarized, or the sentence is invalid.")
      }
      this.rank_summary = summary_obj.summary;
      return summary_obj;
    } catch (err) {
      return Error("An invalid sentence was entered");
    }
  }
}

module.exports = SummarizerManager;