jquery if statement based on screen size

Question

I have a slide out nav bar that I would like open by default on screen width of >=1024 and closed by default < 1024. I have a button that toggles it open and closed it. I'm just starting to learn js. I imagine there's a way to set a default toggle state in an if statement if the window width is >=1024. Any help would be greatly appreciated. Here's what I have so far for the toggle.

$('a.expand').toggle(function() {
        $(this).addClass("open");
        $('#nav').animate({width: 50},{queue:false, duration:300});
        $('.wrapify').animate({marginLeft: 50},{queue:false, duration:300});
        $('.primarynav ul').hide();
        $('.navlogo').hide();   

  }, function() {
        $(this).removeClass("open");
        $('#nav').animate({width: 200},{queue:false, duration:300});
        $('.wrapify').animate({marginLeft: 200},{queue:false, duration:300});
        $('.primarynav ul').show();
        $('.navlogo').show(); 

  });