A Gist of the most challenging code from SNAKE!

SNAKE-gist.js

//CHECK SNAKE BODY FOR MATCHES WITH SNAKE HEAD
function checkSnake () {
  for (var i = 1; i<snake.length; i++) {
    if (_.isEqual(snake[0], snake[i])) {
      return true;
      console.log("totally f'ed")
    }
  }
  return false;
}

//SNAKE GROW FUNCTION
function growSnake () {
  snake.unshift(apple);
  clearApple();
  var row = apple[0];
  var column = apple[1];
  var currentApple = (37 * row + column);
  $('.space').eq(currentApple).css("background-color","green");
  generateApple();
  growScore();
}

//SNAKE MOVE FUNCTION
function moveSnake () {
  snake.unshift(newHead);
  snake.pop();
  fillSnake();
  fillApple();
}

//SNAKE ANIMATION
function animationStart () {
  int = setInterval( function() {
    if(!isPaused) {
    var snakeHead = snake[0];
      if (snake.direction === "left") {
        newHead = [snakeHead[0], snakeHead[1]-1]
        if (newHead[0] === apple[0] && newHead[1] === apple[1]) {
          growSnake();
        } else if (newHead[1] < 0) {
          lost = true;
          youLose();
        } else {
          moveSnake();
        }
      if (checkSnake()) {
          lost = true;
          youLose();
        }
      }
      if (snake.direction === "up") {
        newHead = [snakeHead[0]-1, snakeHead[1]];
        if (newHead[0] === apple[0] && newHead[1] === apple[1]) {
          growSnake();
        } else if (newHead[0] < 0) {
          lost = true;
          youLose();
        } else if (checkSnake()) {
          lost = true;
          youLose();
        } else {
          moveSnake();
        }
      }
      if (snake.direction === "right") {
        newHead = [snakeHead[0], snakeHead[1]+1];
        if (newHead[0] === apple[0] && newHead[1] === apple[1]) {
          growSnake();
        } else if (newHead[1] > 36) {
          lost = true;
          youLose();
        } else if (checkSnake()) {
          lost = true;
          youLose();
        } else {
          moveSnake();
        }
      }
      if (snake.direction === "down") {
        newHead = [snakeHead[0]+1, snakeHead[1]];
        if (newHead[0] === apple[0] && newHead[1] === apple[1]) {
          growSnake();
        } else if (newHead[0] > 36) {
          lost = true;
          youLose();
        } else if (checkSnake()) {
          lost = true;
          youLose();
        } else {
          moveSnake()
        }
      }
    }
  },snakeSpeed);
}