Notes

{
const squares = document.querySelectorAll('.grid div')
const scoreDisplay = document.querySelector('span')
const startBtn = document.querySelector('.start')

const width = 10
let currentIndex = 0 //so first div in our grid
let appleIndex = 0 //so first div in our grid
let currentSnake = [2,1,0]
let direction = 1
let score = 0
let speed = 0.9
let intervalTime = 0
let interval = 0


//to start, and restart the game
function startGame() {
currentSnake.forEach(index => squares[index].classList.remove('snake'))
squares[appleIndex].classList.remove('apple')
clearInterval(interval)
score = 0
randomApple()
direction = 1
scoreDisplay.innerText = score
intervalTime = 1000
currentSnake = [2,1,0]
currentIndex = 0
currentSnake.forEach(index => squares[index].classList.add('snake'))
interval = setInterval(moveOutcomes, intervalTime)
}


//function that deals with ALL the ove outcomes of the Snake
function moveOutcomes() {

//deals with snake hitting border and snake hitting self
if (
(currentSnake[0] + width >= (width * width) && direction === width ) || //if snake hits bottom
(currentSnake[0] % width === width -1 && direction === 1) || //if snake hits right wall
(currentSnake[0] % width === 0 && direction === -1) || //if snake hits left wall
(currentSnake[0] - width < 0 && direction === -width) || //if snake hits the top
squares[currentSnake[0] + direction].classList.contains('snake') //if snake goes into itself
) {
return clearInterval(interval) //this will clear the interval if any of the above happen
}

const tail = currentSnake.pop() //removes last ite of the array and shows it
squares[tail].classList.remove('snake') //removes class of snake from the TAIL
currentSnake.unshift(currentSnake[0] + direction) //gives direction to the head of the array

//deals with snake getting apple
if(squares[currentSnake[0]].classList.contains('apple')) {
squares[currentSnake[0]].classList.remove('apple')
squares[tail].classList.add('snake')
currentSnake.push(tail)
randomApple()
score++
scoreDisplay.textContent = score
clearInterval(interval)
intervalTime = intervalTime * speed
interval = setInterval(moveOutcomes, intervalTime)
}
squares[currentSnake[0]].classList.add('snake')
}


//generate new apple once apple is eaten
function randomApple() {
do{
appleIndex = Math.floor(Math.random() * squares.length)
} while(squares[appleIndex].classList.contains('snake')) //making sure apples dont appear on the snake
squares[appleIndex].classList.add('apple')
}


//assign functions to keycodes
function control(e) {
squares[currentIndex].classList.remove('snake')

if(e.keyCode === 39) {
direction = 1 //if we press the right arrow on our keyboard, the snake will go right one
} else if (e.keyCode === 38) {
direction = -width // if we press the up arrow, the snake will go back ten divs, appearing to go up
} else if (e.keyCode === 37) {
direction = -1 // if we press left, the snake will go left one div
} else if (e.keyCode === 40) {
direction = +width //if we press down, the snake head will instantly appear in the div ten divs from where you are now
}
}

document.addEventListener('keyup', control)
startBtn.addEventListener('click', startGame)
})