Меню, выдвигающееся при скролле вверх

let scroll = 0;
    let scrollCurrent = 0;
    let scrollAction = 'down';
    $(window).on("scroll", function(){    
       
        
        if(this.scrollY>scrollCurrent){//крутим вниз
            if(scrollAction == 'down'){
                if(this.scrollY > scroll+10){
                    
                    $("header.header").removeClass("header--showNav");                    
                    scroll = this.scrollY; 
                }
            }
            else{
               scrollAction = 'down';
               scroll = this.scrollY; 
                
            }
        }
        else{ //крутим вверх
            if(scrollAction == 'up'){
                if(this.scrollY < scroll-100){                    
                    $("header.header").addClass("header--showNav");                    
                    scroll = this.scrollY; 
                }
            }
            else{
               scrollAction = 'up';
               scroll = this.scrollY;                 
            }
        }
        scrollCurrent = this.scrollY;     
           
    });  

$(window).on("scroll", throttle(createHeaderAnimation, 500));
let throttle = (func, limit) => {
      let lastFunc;
      let lastRan;      
      return function() {        
        let context = this;
        let args = arguments;
        if (!lastRan) {
          func.apply(context, args);
          lastRan = Date.now();
        } 
        else {
          clearTimeout(lastFunc);          
          lastFunc = setTimeout(function() {
            if ((Date.now() - lastRan) >= limit) {
              func.apply(context, args);
              lastRan = Date.now();              
            }
          }, limit - (Date.now() - lastRan));
        }
      }
    };