singularize.js

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abbreviations.js adjectives.js convertables.js dates.js demonyms.js firstnames.js honourifics.js irregular_nouns.js irregular_verbs.js misc.js multiples.js numbers.js organisations.js phrasal_verbs.js places.js uncountables.js verbs.js fns.js index.js lexicon.js negate.js passive_voice.js contractions.js fancy_lumping.js grammar_rules.js parts_of_speech.js phrasal_verbs.js tagger.js word_rules.js question.js sentence.js statement.js tense.js adjective.js to_adverb.js to_comparative.js to_noun.js to_superlative.js adverb.js to_adjective.js is_acronym.js article.js date.js date_rules.js is_date.js parse_date.js is_plural.js is_uncountable.js noun.js is_organisation.js organisation.js gender.js is_person.js parse_name.js person.js is_place.js place.js pluralize.js pronoun.js singularize.js is_value.js numbers.js to_number.js units.js value.js term.js conjugate.js from_infinitive.js predict_form.js suffix_rules.js to_actor.js to_infinitive.js negate.js verb.js sentence_parser.js text.js

singularize.js

'use strict';
const is_uncountable = require('./is_uncountable.js');
const irregulars = require('../../data/irregular_nouns.js');
const is_plural = require('./is_plural.js');
const fns = require('../../fns.js');

const singularize_rules = [
  [/([^v])ies$/i, '$1y'],
  [/ises$/i, 'isis'],
  [/ives$/i, 'ife'],
  [/(antenn|formul|nebul|vertebr|vit)ae$/i, '$1a'],
  [/(octop|vir|radi|nucle|fung|cact|stimul)(i)$/i, '$1us'],
  [/(buffal|tomat|tornad)(oes)$/i, '$1o'],
  [/((a)naly|(b)a|(d)iagno|(p)arenthe|(p)rogno|(s)ynop|(t)he)ses$/i, '$1sis'],
  [/(vert|ind|cort)(ices)$/i, '$1ex'],
  [/(matr|append)(ices)$/i, '$1ix'],
  [/(x|ch|ss|sh|s|z|o)es$/i, '$1'],
  [/men$/i, 'man'],
  [/(n)ews$/i, '$1ews'],
  [/([ti])a$/i, '$1um'],
  [/([^f])ves$/i, '$1fe'],
  [/([lr])ves$/i, '$1f'],
  [/([^aeiouy]|qu)ies$/i, '$1y'],
  [/(s)eries$/i, '$1eries'],
  [/(m)ovies$/i, '$1ovie'],
  [/([m|l])ice$/i, '$1ouse'],
  [/(cris|ax|test)es$/i, '$1is'],
  [/(alias|status)es$/i, '$1'],
  [/(ss)$/i, '$1'],
  [/(ics)$/i, '$1'],
  [/s$/i, '']
].map(function(a) {
  return {
    reg: a[0],
    repl: a[1]
  };
});

const singularize = function(str) {
  const low = str.toLowerCase();

uncountable

  if (is_uncountable(low)) {
    return str;
  }

is it already singular?

  if (is_plural(low) === false) {
    return str;
  }

irregular

  const found = irregulars.filter(function(r) {
    return r[1] === low;
  });
  if (found[0]) {
    if (fns.titlecase(low) === str) { //handle capitalisation properly
      return fns.titlecase(found[0][0]);
    }
    return found[0][0];
  }

inflect first word of preposition-phrase

  if (str.match(/([a-z]*) (of|in|by|for) [a-z]/)) {
    const first = str.match(/^([a-z]*) (of|in|by|for) [a-z]/);
    if (first && first[1]) {
      const better_first = singularize(first[1]);
      return better_first + str.replace(first[1], '');
    }
  }

regular

  for (let i = 0; i < singularize_rules.length; i++) {
    if (str.match(singularize_rules[i].reg)) {
      return str.replace(singularize_rules[i].reg, singularize_rules[i].repl);
    }
  }
  return str;
};

¶

console.log(singularize(‘gases’) === “gas”) console.log(singularize(‘kisses’) === “kiss”) console.log(singularize(‘kiss’) === “kiss”) console.log(singularize(‘children’) === “child”) console.log(singularize(‘peace’) === “peace”) console.log(singularize(‘child’) === “child”) console.log(singularize(‘mayors of chicago’) === “mayor of chicago”)
```
module.exports = singularize;
```