game.js

var readline = require('readline');
var jumpEmpty = '▖▘▝'.split('');
var block = '\x1b[31m▖\x1b[0m';
var space = ' ';

var Game = function(options){
  if(!(this instanceof Game)) return new Game(options)

  options = options || {};
  this.width = options.width || 50;
  this.world = [];
  var wdx = 1;
    while (wdx < this.width) {
        this.world.push(space);
        wdx++;
    }
  this.blocks = options.blocks || generateBlocks(200);
  this.blockIndex = 0;
  this.stream = process.stdout;
  this.position = options.position || 20;
  this.delay = 1000 / (options.speed || 10);
    this.state = {
        cursor: 0,
        jumping: false,
        jumpPosition: 0,
        jumpSequence: jumpEmpty,
    };
  this.rl = readline.createInterface({
      input: process.stdin,
      output: process.stdout,
    });
  this.rl.on('close', () => {
    process.exit(0);
  });
};

Game.prototype.onTick = function () {
  this.clearLine(this.stream);
  var world = this.world.concat([]);
  world.splice(this.position, 1, this.getPlayer());
  this.state.jumping = false;
  this.stream.write(world.join(''));
};

Game.prototype.getPlayer = function() {
    var pos = this.state.jumpPosition;
    if (this.state.jumping || pos) {
        this.state.jumpPosition++;
    }
    if (this.state.jumpPosition > 2) {
        this.state.jumpPosition = 0;
    }
  return this.state.jumpSequence[pos];
};

Game.prototype.lose = function() {
  console.log('Boom!');
  console.log(`Score: ${this.state.cursor}`);
  this.stop();
  process.exit(0);
};

Game.prototype.colliding = function() {
    return this.world[this.position] !== space
        && this.state.jumpPosition == 0;
};

Game.prototype.start = function() {
  var self = this;

  var iteration = function() {
    self.world.shift();
      if (self.colliding()) {
          return self.lose();
      }
    var land = self.blocks[self.blockIndex];
      if (land == self.state.cursor) {
          self.world.push(block);
          self.blockIndex++;
      } else {
          self.world.push(space);
      }
    self.onTick();
    self.state.cursor++;
  };

  readline.emitKeypressEvents(process.stdin);
  if (process.stdin.isTTY)
    process.stdin.setRawMode(true);
  process.stdin.on('keypress', this.handleKey.bind(this));
  iteration();
  this.id = setInterval(iteration, this.delay);

  return this;
};

Game.prototype.handleKey = function(a, key) {
    if (key.name !== 'up'
    && key.name !== 'w') return;
    if (this.state.jumping || this.state.jumpPosition) return;
    this.state.jumping = true;
}

Game.prototype.stop = function(clear) {
  clearInterval(this.id);
  this.id = undefined;
  if (clear) {
    this.clearLine(this.stream);
  }

  return this;
};

Game.prototype.clearLine = function(stream) {
  readline.clearLine(stream, 0);
  readline.cursorTo(stream, 0);

  return this;
};

function generateBlocks(len) {
    var blocks = [];
    var start = 1;
    var used = 0;
    for (var i = 1; i < len; i++) {
        if (Math.random() > 0.75 && !used) {
            blocks.push(i);
            used = 3;
        } else {
            used = Math.max(0, used - 1);
        }
    }
    return blocks;
}

(new Game({ speed: 11 })).start();