See this section in the documentation:
.animate( properties, options )
properties
and options
are two objects and steps
has to be a property on options
. So your code becomes
$(scrolledElement).animate(
scrollOptions,
{
duration: options.scrollingSpeed,
easing: options.easing,
step: function() {
// ...
},
complete: function () {
continuousVerticalFixSectionOrder();
// ...
}
}
);