1_debounce.js

var debounce;

$(window).on('scroll', function (ev) {
  if (debounce) {
    clearTimeout(debounce);
  }
  
  debounce = setTimeout(function () {
    if($(window).scrollTop() > secondaryNavTopPosition ) {
      // ...
    } else {
      // ...
    }
  });
});

2_clear-timeout.js

var triggerTimeout;

$(window).on('scroll', function (ev) {
  if (triggerTimeout) {
    clearTimeout(triggerTimeout);
  }
  
  if($(window).scrollTop() > secondaryNavTopPosition ) {
    secondaryNav.addClass('is-fixed');    
    triggerTimeout = setTimeout(function() {
      secondaryNav.addClass('animate-children');
      $('#cd-logo').addClass('slide-in');
      $('.cd-btn').addClass('slide-in');
    }, 60);
  } else {
    // ...
  }
});

3_combined.js

var debounce;

$(window).on('scroll', function (ev) {
  if (debounce) {
    clearTimeout(debounce);
  }
  
  debounce = setTimeout(function () {
    if($(window).scrollTop() > secondaryNavTopPosition ) {
      secondaryNav.addClass('is-fixed');    
      debounce = setTimeout(function() {
        secondaryNav.addClass('animate-children');
        $('#cd-logo').addClass('slide-in');
        $('.cd-btn').addClass('slide-in');
      }, 60);
    } else {
      // ...
    }
  });
});

4_applied.js

var win = $(window),
  logo = $('#cd-logo'),
  btn = $('.cd-btn'),
  secondaryNav = $('.cd-secondary-nav'),
  secondaryNavTopPosition = secondaryNav.offset().top,
  debounce;
 
win.on('scroll', function(){
  if (debounce) {
    clearTimeout(debounce);
  }
  
  debounce = setTimeout(function () {
    var collapsedTop = win.scrollTop() > secondaryNavTopPosition;
      
    secondaryNav.toggleClass('is-fixed', collapsedTop);
    
    debounce = setTimeout(function() {
      secondaryNav.toggleClass('animate-children', collapsedTop);
      logo.toggleClass('slide-in', collapsedTop);
      btn.toggleClass('slide-in', collapsedTop);
    }, 60);
  });
});