diff --git a/packages/gitbook/src/components/hooks/useScrollActiveId.ts b/packages/gitbook/src/components/hooks/useScrollActiveId.ts index 96b986eac..eacfdcc26 100644 --- a/packages/gitbook/src/components/hooks/useScrollActiveId.ts +++ b/packages/gitbook/src/components/hooks/useScrollActiveId.ts @@ -12,11 +12,12 @@ export function useScrollActiveId( ) { const { rootMargin, threshold = 0.5 } = options; - const [activeId, setActiveId] = React.useState(null); + const [activeId, setActiveId] = React.useState(ids[0]); const sectionsIntersectingMap = React.useRef>(new Map()); React.useEffect(() => { - setActiveId(null); + const defaultActiveId = ids[0]; + setActiveId((activeId) => (ids.indexOf(activeId) !== -1 ? activeId : defaultActiveId)); if (typeof IntersectionObserver === 'undefined') { return;