Support "stickyBitStickyOffset" as a function so it is recalculated dynamically.

[dpoltoratsky]

Requested Update

Support "stickyBitStickyOffset" (and potentially other props) as a function, so it is recalculated dynamically.

Why Is This Update Needed?

To support use cases when sticky element position may change due to changes on the page.

For example, going through a responsive breakpoint makes the base font size smaller/larger, which affects the height of an element above the sticky one.

Below is example from my implementation with jQuery.

const $adminBar = $('#wpadminbar');
const $header = $('#masthead');

$header.sticky({
        useStickyClasses: true,
        stickyBitStickyOffset: () =>
            - $header.children('.site-branding').outerHeight()
            + ($adminBar.length ? $adminBar.outerHeight() : 0)
    });

In my particular case, the height of the .site-branding changes dynamically when going through responsive breakpoints.

Are There Examples Of This Requested Update Elsewhere?

I am not sure, does not seem so.

[yowainwright]

Although, I think this change could help and be fun to make. However, it reads like the problem could be solved within a resize callback.