How to condition a class

I’m new to JS and I want to know if there’s any possible way to condition a class

I’ll put you in context.
I’m trying to disable the scroll-bar for my mobile navbar and I got this so far:

<style>
  .no-scroll {
    overflow: hidden;
  }
</style>

<script>
  $('.checkbtn').on('click', function() {
    $('body').toggleClass('no-scroll');
  });
  if (I NEED YOUR HELP HERE) {
    $('.checkbtn').on('click', function() {
      $('body').removeClass('no-scroll');
    });
  }
</script>

Am I doing fine so far? Anyway, my question is how can I tell IF that ‘body’ has to have no-scroll class for it to work

Edit: My hamburger navbar icon class is called ".checkbtn"

>Solution :

you can use hasClass method

for example

if($('body').hasClass('no-scroll'){
  // your code
}