AI Dungeon Random Species Replacer

/***
 *
 *  Author: Draco18s
 *
 *  call this from Output Modifier
 *  const regex = /(^| )(human|el|dwar|svelk)[fve]*s*(?!\w)/gi;
 *  if(modifiedText.match(regex)) {
 *    modifiedText = modifiedText.replace(regex,"$1"+getRandomSpecies());
 *  }
 *
 *  Altering the regex to pick up additional unwanted races should be pretty straight forward.
 *  Adjusting the species list is likewise "add, remove, or comment" as desired. They're grouped
 *  by rough category (so you could disable all canines quickly) such that any given group has
 *  same odds of appearing as any other group at the same level (so "a mammal" and "a bird" are
 *  just as likely as each other, but "magpie" will be about half as common as "any rodent"
 *  (15 total birds, vs 8 mammal groups).
 *
 *  No attempt is made to massage the sentence grammar ("a owl").
***/

const species = {
  mammal: {
    feline: [
      "feline",
      "lion",
      "panther",
      "tiger",
      "cheetah",
      "cougar",
      "jaguar",
    ],
    canine: [
      "canine",
      "wolf",
      "fox",
      "hyena",
      "jackal",
      "coyote",
      "african wild dog",
    ],
    equine: [
      "horse",
      "zebra",
    ],
    ungulate: [
      "deer",
      "cow",
      "antelope",
      "boar",
      "goat",
      "sheep",
      "reindeer",
      "giraffe",
    ],
    ursine: [
      "brown bear",
      "black bear",
      "polar bear",
      "sun bear",
    ],
    mustelide: [
      "otter",
      "ferret",
      "marten",
      "mink",
      "skunk",
    ],
    rodent: [
      "bat",
      "mouse",
      "rat",
      "beaver",
    ],
    other: [
      "kangaroo",
      "bunny",
      "red panda",
      "raccoon",
      "elephant",
      "rhinoceros",
      "civet",
      "sloth",
      "armadillo",
      "anteater",
      "pangolin",
    ]
  },
  bird: [
    "magpie",
    "hoatzin",
    "raven",
    "jay",
    "eagle",
    "hawk",
    "secretary bird",
    "rufous kingfisher",
    "plover",
    "owl",
    "robin",
    "kingfisher",
    "sunbittern",
    "falcon",
    "gannet",
  ],
  reptile: {
    modern: [
      "kobold",
      "lizardman",
      "gator",
      "crocodile",
      "iguanna",
      "snake",
      "komodo",
    ],
    dinosaur: [
      "theropod",
      "sauropod",
      "genasauria",
    ]
  },
  mythic: [
    "gryphon",
    "hippogriff",
    "dragon",
    "eastern dragon",
    "wyvern",
    "phoenix",
  ]
}
function getRandomSpecies() {
  var chunk = species;
  var max = chunk.length;
  while(!Array.isArray(chunk)) {
    var subchunk = Object.getOwnPropertyNames(chunk);
    max = subchunk.length;
    var r = Math.floor(Math.random()*max);
    chunk = chunk[subchunk[r]];
  }
  var max = chunk.length;
  var rr = Math.floor(Math.random()*max);
  chunk = chunk[rr];
  return chunk;
}