Uncaught TypeError: can't access property "classList" of undefined app.js:107:5

[Fishbite]

Hey Ania,

This is the error running your unadulterated code with the exception that I corrected the link to the css file in the html file.

Uncaught TypeError: can't access property "classList", squares[currentLaserIndex] is undefined
moveLaser https://fishbite.github.io/space-invaders/app.js:107
setInterval handlershoot https://fishbite.github.io/space-invaders/app.js:130
EventListener.handleEvent https://fishbite.github.io/space-invaders/app.js:134
app.js:107:5

It occurs when the laser shot exits the top of the screen and I'm not sure how to fix it!!! Any ideas?

Thanks for the video tutorial BTW. It's much appreciated by many folks out there especially myself :)

[CoderCH62]

Insert this code right at the top of the moveLaser function:

    if (currentLaserIndex < width){
      squares[currentLaserIndex].classList.remove('laser')
      clearInterval(laserId)
      return
    }

[Fishbite]

That's similar to my own fix:

if (currentLaserIndex - width < 0) {
            squares[currentLaserIndex].classList.remove("laser");
            return;

which seems to have cured the problem. I didn't use clearInterval() though. Interesting!?
https://fishbite.github.io/space_invaders/

[CoderCH62]

You should yet clear the Interval of laserID, otherwise every laser beam exist forever and it's index value will continue decreasing every interval. It will probably never result in a problem for this little game, however, is not good practice to keep the interval alive.