indefiniteArticle.js

  window.indefiniteArticle = function(phrase) {
    // Getting the first word
    var match = /\w+/.exec(phrase)
    if (match) var word = match[0]
    else return "an"

    var l_word = word.toLowerCase()
    // Specific start of words that should be preceeded by 'an'
    var alt_cases = ["honest", "hour", "hono"]
    for (var i in alt_cases) {
      if (l_word.indexOf(alt_cases[i]) == 0) return "an"
    }

    // Single letter word which should be preceeded by 'an'
    if (l_word.length == 1) {
      if ("aedhilmnorsx".indexOf(l_word) >= 0) return "an"
      else return "a"
    }

    // Capital words which should likely be preceeded by 'an'
    if (
      word.match(
        /(?!FJO|[HLMNS]Y.|RY[EO]|SQU|(F[LR]?|[HL]|MN?|N|RH?|S[CHKLMNPTVW]?|X(YL)?)[AEIOU])[FHLMNRSX][A-Z]/
      )
    ) {
      return "an"
    }

    // Special cases where a word that begins with a vowel should be preceeded by 'a'
    regexes = [/^e[uw]/, /^onc?e\b/, /^uni([^nmd]|mo)/, /^u[bcfhjkqrst][aeiou]/]
    for (var i in regexes) {
      if (l_word.match(regexes[i])) return "a"
    }

    // Special capital words (UK, UN)
    if (word.match(/^U[NK][AIEO]/)) {
      return "a"
    } else if (word == word.toUpperCase()) {
      if ("aedhilmnorsx".indexOf(l_word[0]) >= 0) return "an"
      else return "a"
    }

    // Basic method of words that begin with a vowel being preceeded by 'an'
    if ("aeiou".indexOf(l_word[0]) >= 0) return "an"

    // Instances where y follwed by specific letters is preceeded by 'an'
    if (l_word.match(/^y(b[lor]|cl[ea]|fere|gg|p[ios]|rou|tt)/)) return "an"

    return "a"
  }
}) // End Document Ready function