diff --git a/src/routes/_utils/scrollIntoView.js b/src/routes/_utils/scrollIntoView.js index fe49afd..286c39f 100644 --- a/src/routes/_utils/scrollIntoView.js +++ b/src/routes/_utils/scrollIntoView.js @@ -3,8 +3,12 @@ import { getOffsetHeight } from './scrollContainer' import { smoothScroll } from './smoothScroll' +let mainNavElement function getTopOverlay () { - return document.getElementById('main-nav').clientHeight + if (!mainNavElement) { + mainNavElement = document.getElementById('main-nav') + } + return mainNavElement.clientHeight } export function isVisible (element) { @@ -20,6 +24,8 @@ export function isVisible (element) { export function firstVisibleElementIndex (items, itemElementFunction) { let offsetHeight = getOffsetHeight() let topOverlay = getTopOverlay() + let first = -1 + let firstComplete = -1 let len = items.length let i = -1 while (++i < len) { @@ -29,14 +35,13 @@ export function firstVisibleElementIndex (items, itemElementFunction) { } let rect = element.getBoundingClientRect() if (rect.top < offsetHeight && rect.bottom >= topOverlay) { - let firstComplete = i - if (rect.top < topOverlay && i < (len - 1)) { - firstComplete = i + 1 - } - return { first: i, firstComplete } + first = i + firstComplete = ( + rect.top < topOverlay && i < (len - 1)) ? i + 1 : i + break } } - return -1 + return { first, firstComplete } } export function scrollIntoViewIfNeeded (element) {