It gives a text of the choo choo train for your tweet. (Not really sure why I wrote it.)

choochootrain.js

DATA = {
  ENGINES: ["🚂"],
  CARS: ["🚃","🚋"],
  SCENES: ['desert', 'forest', 'beach'],
  ORBS: ["🌕","🌙","☀","☁"],
  DESERT_TILES: ["🌵","🌵","🌴","🌴","🐪","🐢","🐎"],
  FOREST_TILES: ["🌲","🌲","🌲","🌲","🐇","🌳","🌳"],
  BEACH_TILES: ["🌴","🌴","🍍","🐢","🗿","🐚"],
  SEA_TILES:["🐬","🐳","🐙"],

  HELL_TILES: ["🔥","👻","😈","💀"],
  HEAVEN_TILES: ["📯👼","✨","🐕","👼"],
  SPACE_TILES: ["👾","👽","💫","🚀","🛰"],
  UNDERSEA_TILES: ["🐟","🐙","🐬","🐋"]
};

function randint(min, max) {
  return Math.floor( Math.random() * (max - min + 1) ) + min;
}

function randchoice(arr) {
  return arr[Math.floor(Math.random() * arr.length)];
}

function pick_engine() {
  var leading_spaces = randint(0,9);
  var engine = "";
  for (var i = 0; i < leading_spaces; i++) {
    engine += " ";
  }
  engine += randchoice(DATA.ENGINES);
  return engine;
}

function pick_body() {
  var body = "";
  var cars = randint(1,8);
  for (var i = 0; i < cars; i++) {
    body += randchoice(DATA.CARS);
  }
  // body += "💨";
  return body;
}

function make_sky() {
  var sky = "";
  var orb = randchoice(DATA.ORBS);

  // It appears most clients don't let tweets lead with whitespace.
  // This commented out code would have put arbitrary whitespace in the sky
  // But for now we'll just put the sun or moon or cloud on the far left
  //    for _ in range(20):
  //        sky += " "
  //    orb_placement = random.randint(0,len(sky)-1)
  //    sky = sky[:orb_placement] + orb + sky[orb_placement:]
  sky = orb;
  return sky;
}

function make_train() {
  var scene = randchoice(DATA.SCENES);
  if (randint(1, 12) == 12) {
    scene = "special";
  }
  var sky = make_sky();

  var landscape_train;
  if (scene == "desert"){
    landscape_train = make_desert();
  } else if (scene == "forest") {
    landscape_train = make_forest();
  } else if (scene == "beach") {
    landscape_train = make_beach();
  } else if (scene == "special") {
    sky = "";
    landscape_train = make_special();
  }

  var landscape = landscape_train[0];
  var train = landscape_train[1];
  mise_en_scene = (
    sky + "\n" +
    landscape[0] + "\n" +
    landscape[1] + "\n" +
    train + "\n" +
    landscape[2] + "\n" +
    landscape[3]);
  return mise_en_scene;
}

function  make_desert()
{
  var train = pick_engine() + pick_body();
  var landscape = [];
  var tileset = DATA.DESERT_TILES;
  for (var i = 0; i < 4; i++) {
    var row = "";
    for (var spot = 0; spot < 20; spot++) {
      var tile = randint(0, 1000);
      if (tile % 10 == 0) {
        row += randchoice(tileset);
      } else {
        row += " ";
      }
    }
    landscape.push(row);
  }
  return [landscape, train];
}

function  make_forest()
{
  var train = pick_engine() + pick_body();
  var landscape = [];
  var tileset = DATA.FOREST_TILES;
  for (var i = 0; i < 4; i++) {
    var row = "";
    for (var spot = 0; spot < 20; spot++) {
      var tile = randint(0, 1000);
      if (tile % 10 == 0) {
        row += randchoice(tileset);
      } else {
        row += " ";
      }
    }
    landscape.push(row);
  }
  return [landscape, train];
}

function  make_beach() {
  var train = pick_engine() + pick_body();
  var landscape = [];
  var tileset = DATA.BEACH_TILES;
  for (var i = 0; i < 3; i++) {
    var row = "";
    for (var spot = 0; spot < 20; spot++) {
      var tile = randint(0, 1000);
      if (tile % 10 == 0) {
        row += randchoice(tileset);
      } else {
        row += " ";
      }
    }
    landscape.push(row);
  }
  tileset = DATA.SEA_TILES;
  var lastrow = "";
  for (var spot = 0; spot < 12; spot++) {
    var tile = randint(0, 1000);
    if (tile % 10 == 0) {
      lastrow += randchoice(tileset);
    } else {
      lastrow += " ";
    }
  }
  landscape.push(lastrow);
  return [landscape, train];
}


function make_special() {
  var train = pick_engine() + pick_body();
  var scene = randchoice(["hell","heaven","space","undersea"]);
  var border, tileset, landscape;
  if (scene == "hell") {
    border = "🔥👹🔥👹🔥👹🔥👹🔥👹🔥👹";
    tileset = DATA.HELL_TILES;
  } else if (scene == "heaven") {
    border = "☁👼☁👼☁👼☁👼☁👼☁👼";
    tileset = DATA.HEAVEN_TILES;
  } else if (scene == "space") {
    border = "⭐🌟⭐🌟⭐🌟⭐🌟⭐🌟⭐🌟";
    tileset = DATA.SPACE_TILES;
  } else if (scene == "undersea") {
    border = "🌊🌊🌊🌊🌊🌊🌊🌊🌊🌊🌊🌊";
    tileset = DATA.UNDERSEA_TILES;
  }
  landscape = [border];
  for (var i = 0; i < 2; i++) {
    var row = "";
    for (var spot = 0; spot < 20; spot++) {
      var tile = randint(0, 1000);
      if (tile % 10 == 0) {
        row += randchoice(tileset);
      } else {
        row += " ";
      }
    }
    landscape.push(row);
  }
  landscape.push(border);

  return [landscape, train];
}


var exports = module.exports = {}

exports.make_train = make_train;

output.txt

🌕
     🌳 🐇
🌳             🌳    🌲
     🚂🚃🚃🚃🚃🚃🚋🚋🚃
    🐇     🌳