@anthonyjclark/proofreader/lib/proofreader.js

Simple text proofreader based on 'write-good' (hemingway-app-like suggestions) and 'nodehun' (spelling).

var cheerio = require('cheerio');
var fs = require('fs');
var path = require('path');
var writeGood = require('write-good');
var nodehun = require('nodehun');
var spellcheck = require('nodehun-sentences');

module.exports = Proofreader;

function Proofreader() {
  /**
   * @type nodehun
   * @private
   */
  this._dictionary = null;
  this._whitelist = '';
  this._blacklist = '';
  this._writeGoodSettings = null;
}

/**
 * Adds a dictionary. First dictionary has to provide both dic (words) and aff (grammar) filepaths, all subsequent ones are
 * expected to provide only dic filepath.
 *
 * @param {String} dicFilePath
 * @param {String} affFilePath
 */
Proofreader.prototype.addDictionary = function (dicFilePath, affFilePath) {
  if (!this._dictionary) {
    this._dictionary = new nodehun(fs.readFileSync(affFilePath), fs.readFileSync(dicFilePath));
  } else {
    this._dictionary.addDictionary(fs.readFileSync(dicFilePath));
  }
};

/**
 * Sets a selector with whitelisted elements
 * @param {String} value
 */
Proofreader.prototype.setWhitelist = function (value) {
  if (typeof value !== 'string') {
    throw new Error('Whitelist must be a string.');
  }
  this._whitelist = value;
};

/**
 * Sets a selector with blacklisted elements
 * @param {String} value
 */
Proofreader.prototype.setBlacklist = function (value) {
  if (typeof value !== 'string') {
    throw new Error('Blacklist must be a string.');
  }
  this._blacklist = value;
};

/**
 * Sets write-good settings object.
 * @see https://github.com/btford/write-good#checks
 * @param {Object} settings
 */
Proofreader.prototype.setWriteGoodSettings = function (settings) {
  if (settings !== undefined && typeof settings !== 'object') {
    throw new Error('Blacklist must be a string.');
  }
  this._writeGoodSettings = settings;
};

/**
 * Returns an array of writeGood and spelling suggestions (via promise) for provided HTML string
 * @param {String} html
 * @returns {Promise}
 */
Proofreader.prototype.proofread = function (html) {

  // Configure the proofreader (a bit of a hack from the original source)
  this.setWhitelist("p, li, h1, h2, h3, h4, th, td, dl, figcaption");
  this.setBlacklist("pre, code");
  this.addDictionary(
    path.join(__dirname, '../dictionaries/en_US.dic'),
    path.join(__dirname, '../dictionaries/en_US.aff'));

  var $ = cheerio.load(html);
  var dictionary = this._dictionary;
  var whitelist = this._whitelist;
  var blacklist = this._blacklist;
  var writeGoodSettings = this._writeGoodSettings;

  return new Promise(function (resolve, reject) {
    var suggestions = [];
    var promises = [];

    //Blacklisted elements are removed before text is processed
    if (blacklist) {
      $(blacklist).remove();
    }

    //Only whitelisted elements are processed
    $(whitelist).each(function () {
      var text = $(this).text();

      //remove linebreaks from text
      text = text.replace(/(\r\n|\n|\r)+/gm, " ");

      //replace ’ with '
      text = text.replace(/’/g, "'");

      //replace multiple spaces with a single one
      text = text.replace(/\s{2,}/g, ' ');

      //trim text
      text = text.trim();

      if (text.length) {
        var writeGoodSuggestions = writeGood(text, writeGoodSettings);

        var spellcheckResolve = null;
        var promise = new Promise(function (r) { spellcheckResolve = r; });
        promises.push(promise);

        spellcheck(dictionary, text, function (error, spellcheckerSuggestions) {
          suggestions.push({
            text: text,
            suggestions: {
              writeGood: writeGoodSuggestions,
              spelling: spellcheckerSuggestions || []
            }
          });
          spellcheckResolve();
        });
      }
    });

    Promise.all(promises).then(function() {resolve(suggestions);})
  });
};