javascript function to animate sticky header

stickyanimate.js

updateStickyText: function() {
        var t = this
        if (!this.ignoreStickyTitleChange) {
            var e = document.body.getBoundingClientRect()
              , r = this.querySelectorAllCached(".sticky-change, .sticky-stop")
              , n = document.querySelector(".sticky-stop")
              , o = this.getScrollElement().scrollTop
              , i = this.querySelectorCached("h1.sticky")
            if (null !== i) {
                var a = i.getBoundingClientRect()
                  , s = a.top + o
                  , c = a.bottom + o - s
                if (null !== n) {
                    var u = n.querySelector("figure")
                      , l = u.getBoundingClientRect().top - e.top
                      , f = u.getBoundingClientRect().bottom - e.top
                      , p = f - l
                      , h = n.getBoundingClientRect()
                      , y = h.top - e.top
                      , d = y + p / 2 - c
                    if (this.textIsSticky && o < d)
                        return this.textIsSticky = !1,
                        i.classList.remove("static"),
                        void (i.style.top = null)
                    if (o > d)
                        return i.classList.add("static"),
                        this.textIsSticky = !0,
                        void (i.style.top = d + "px")
                }
                if (!this.textIsSticky) {
                    var v = !1
                    r.forEach(function(r) {
                        if (!v) {
                            var n = r.getBoundingClientRect()
                              , o = n.top - e.top
                              , i = n.bottom - e.top
                            r.classList.contains("sticky-change") && s > o - c && s < i && (v = !0,
                            t.setStickyTitle(r.dataset.stickyTitle))
                        }
                    })
                }
            }
        }
    }