passive-voice/passive.js

detect passive voice

var irregulars = [
  'awoken',
  'been',
  'born',
  'beat',
  'become',
  'begun',
  'bent',
  'beset',
  'bet',
  'bid',
  'bidden',
  'bound',
  'bitten',
  'bled',
  'blown',
  'broken',
  'bred',
  'brought',
  'broadcast',
  'built',
  'burnt',
  'burst',
  'bought',
  'cast',
  'caught',
  'chosen',
  'clung',
  'come',
  'cost',
  'crept',
  'cut',
  'dealt',
  'dug',
  'dived',
  'done',
  'drawn',
  'dreamt',
  'driven',
  'drunk',
  'eaten',
  'fallen',
  'fed',
  'felt',
  'fought',
  'found',
  'fit',
  'fled',
  'flung',
  'flown',
  'forbidden',
  'forgotten',
  'foregone',
  'forgiven',
  'forsaken',
  'frozen',
  'gotten',
  'given',
  'gone',
  'ground',
  'grown',
  'hung',
  'heard',
  'hidden',
  'hit',
  'held',
  'hurt',
  'kept',
  'knelt',
  'knit',
  'known',
  'laid',
  'led',
  'leapt',
  'learnt',
  'left',
  'lent',
  'let',
  'lain',
  'lighted',
  'lost',
  'made',
  'meant',
  'met',
  'misspelt',
  'mistaken',
  'mown',
  'overcome',
  'overdone',
  'overtaken',
  'overthrown',
  'paid',
  'pled',
  'proven',
  'put',
  'quit',
  'read',
  'rid',
  'ridden',
  'rung',
  'risen',
  'run',
  'sawn',
  'said',
  'seen',
  'sought',
  'sold',
  'sent',
  'set',
  'sewn',
  'shaken',
  'shaven',
  'shorn',
  'shed',
  'shone',
  'shod',
  'shot',
  'shown',
  'shrunk',
  'shut',
  'sung',
  'sunk',
  'sat',
  'slept',
  'slain',
  'slid',
  'slung',
  'slit',
  'smitten',
  'sown',
  'spoken',
  'sped',
  'spent',
  'spilt',
  'spun',
  'spit',
  'split',
  'spread',
  'sprung',
  'stood',
  'stolen',
  'stuck',
  'stung',
  'stunk',
  'stridden',
  'struck',
  'strung',
  'striven',
  'sworn',
  'swept',
  'swollen',
  'swum',
  'swung',
  'taken',
  'taught',
  'torn',
  'told',
  'thought',
  'thrived',
  'thrown',
  'thrust',
  'trodden',
  'understood',
  'upheld',
  'upset',
  'woken',
  'worn',
  'woven',
  'wed',
  'wept',
  'wound',
  'won',
  'withheld',
  'withstood',
  'wrung',
  'written'
];

var exceptions = [
  'indeed',
];

var re = new RegExp('\\b(am|are|were|being|is|been|was|be)\\b\\s*([\\w]+ed|' + irregulars.join('|') + ')\\b', 'gi');
var byRe; // lazly construct

module.exports = function (text, options) {
  var r = (options && options.by) ?
          (byRe || constructByRe()) : re; // not sorry

  var suggestions = [];
  while (match = r.exec(text)) {
    if (exceptions.indexOf(match[2].toLowerCase()) === -1) {
      suggestions.push({
        index: match.index,
        offset: match[0].length
      });
    }
  }
  return suggestions;
}

// lol
function constructByRe () {
  return byRe = new RegExp(re.toString().slice(1, -3) + '\\s*by\\b', 'gi');
}