index.js

var natural = require('natural');
var nounInflector = new natural.NounInflector();
var articles = require('articles/lib/Articles.js');
var randy = require('randy');
var _ = require('lodash');

// ---------------------------------------------
//                  DEFAULTS
// ---------------------------------------------

function Sentencer() {
  var self = this;

  self._nouns      = require('./words/nouns.js');
  self._adjectives = require('./words/adjectives.js');

  self.actions = {
    noun: function() {
      return randy.choice(self._nouns);
    },
    a_noun: function() {
      return articles.articlize( self.actions.noun() );
    },
    nouns: function() {
      return nounInflector.pluralize( randy.choice(self._nouns) );
    },
    adjective: function() {
      return randy.choice(self._adjectives);
    },
    an_adjective: function() {
      return articles.articlize( self.actions.adjective() );
    }
  };

  self.configure = function(options) {
    // merge actions
    self.actions     = _.merge(self.actions, options.actions || {});
    // overwrite nouns and adjectives if we got some
    self._nouns      = options.nounList || self._nouns;
    self._adjectives = options.adjectiveList || self._adjectives;
  };

  self.use = function(options) {
    var newInstance = new Sentencer();
    newInstance.configure(options);
    return newInstance;
  };
}

// ---------------------------------------------
//                  THE GOODS
// ---------------------------------------------

Sentencer.prototype.make = function(template) {
  var self = this;

  var sentence = template;
  var occurrences = template.match(/\{\{(.+?)\}\}/g);

  if(occurrences && occurrences.length) {
    for(var i = 0; i < occurrences.length; i++) {
      var action = occurrences[i].replace('{{', '').replace('}}', '').trim();
      var result = '';
      var actionIsFunctionCall = action.match(/^\w+\((.+?)\)$/);

      if(actionIsFunctionCall) {
        var actionNameWithParens = action.match(/^(\w+)\(/);
        var actionName = actionNameWithParens[1];
        var actionExists = self.actions[actionName];
        var actionContents = action.match(/\((.+?)\)/);
        actionContents = actionContents && actionContents[1];

        if (actionExists && actionContents) {
          try {
            var args = _.map(actionContents.split(','), maybeCastToNumber);
            result = self.actions[actionName].apply(null, args);
          }
          catch(e) { }
        }
      } else {
        if(self.actions[action]) {
          result = self.actions[action]();
        } else {
          result = '{{ ' + action + ' }}';
        }
      }
      sentence = sentence.replace(occurrences[i], result);
    }
  }
  return sentence;
};

function maybeCastToNumber(input) {
  var trimmedInput = input.trim();
  return !Number.isNaN(Number(trimmedInput)) ? Number(trimmedInput) : trimmedInput;
}

// ---------------------------------------------
//                    DONE
// ---------------------------------------------

var instance = new Sentencer();
module.exports = instance;