fix: docs sidebar layout issue when announcementBar visible

[sbeaury]

Pre-flight checklist

• [x] I have read the Contributing Guidelines on pull requests.
• [ ] If this is a code change: I have written unit tests and/or added dogfooding pages to fully verify the new behavior.
• [ ] If this is a new API or substantial change: the PR has an accompanying issue (closes #0000) and the maintainers have approved on my working plan.

Motivation

• Fix overlapping issue in docs sidebar (Sidebar Ad vs Collapse Button). Subtracted announcement bar height from sidebarViewport max-height
• Not sure why margin-bottom for DocSidebar is set to var(--docusaurus-announcement-bar-height)

Test Plan

Can easily be double-checked / manually tested on the specific breakpoint causing issue.

Test links

N/A

Related issues/PRs

Issues 8370 and 8374

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[Djunnni]

thank you for your effort however i think it's not good to changing css (ex. use 40px) simply.

#8377 how about checking slorber's comment?

[sbeaury]

hey @Djunnni, the purpose of this PR is actually to remove the extra 30px from the navbar height (100vh) coming from --docusaurus-announcement-bar-height to avoid things getting squeezed at the bottom. I found this CSS-only solution much simpler than changing the whole layout and it works on the specific breakpoint causing issue (smaller viewport height). The only issue is to reset the max-height to 100vh when announcementBar is NOT visible but should be easy to add a conditional and fix it.

[Djunnni]

if announcementBar is hide, sidebar has empty space like that. could you test this?

[slorber]

(don't worry about the tests, already fixed in main)

---

This is a nice attempt but unfortunately it doesn't seem to work. It replaces a problem by another (not necessarily better).

Good pages to test:

• https://docusaurus.io/docs/sidebar/items

• https://deploy-preview-8493--docusaurus-2.netlify.app/docs/sidebar/items

• https://docusaurus.io/tests/docs/toc/toc-_-5/

• https://deploy-preview-8493--docusaurus-2.netlify.app/tests/docs/toc/toc-_-5/

When you start scrolling when announcementBar is visible (clear localstorage or anonymous session), this leads to this weird empty space:

[sbeaury]

As mentioned above, my PR was to fix the overlap when announcementBar is visible. What we know for sure is that .sidebarViewport is too high when announcement bar is visible hence the squeezing at the bottom. But we can use the same idea and monitor how much space that announcement bar takes while scrolling (e.g. interceptor) and subtract it using a CSS-in-JS solution. Could even be integrated into useAnnouncementBar. Or... just refactor the whole layout. I can work out something on my side but it's fine to close the PR for now bc I don't want to hold it off.

style={{maxHeight: `calc(100vh - ${announcementBarHeightOnViewport})`}}

[slorber]

I'm not sure exactly what's the problem and what's the solution is 😅 unfortunately I need to focus on the MDX 2 migration atm.

The only thing I know is that the outcome of merging this PR is not better, eventually worst than the current state.

We want the layout to be fully fixed. We want a solution that doesn't do any of these 2 behaviors:

Feel free to close the PR if you think you can't solve it. Thanks for trying, that almost looked like a good solution 😄

[sbeaury]

Last commit should fix the problem hopefully 🤞. I dynamically subtracted the portion of the announcement bar visible on viewport from the sidebar container's max-height.

[slorber]

getComputedStyle can't be used during the SSR/SSG/build phase so this change makes the site unable to build 😅

Not 100% sure it's possible but I'd prefer if we could find a CSS-only solution so that the initial render (before JS is executed) looks fine. "fixing things" with JS usually leads to annoying layout shifts. But a JS solution is still better than no solution 😅 .

[sbeaury]

you're right I forgot to add a conditional using useIsBrowser for client side only but I finally opted out for another solution in my last commit which is to declare a docusaurusAnnouncementBarHeight value in CSS module so that we can export it and use to initialize announcement barheightOnViewport. IMHO a CSS-only solution is not feasible atm since the banner height is kind of dynamic on viewport so the sidebar needs to resize accordingly (unless the whole layout is refactored). There are some build errors in the log that I believe are not linked to my last commit?

[slorber]

Now it builds but does not really work 😄 I see many weird issues on both pages:

• https://deploy-preview-8493--docusaurus-2.netlify.app/tests/docs/toc/toc-_-5/
• https://deploy-preview-8493--docusaurus-2.netlify.app/docs/sidebar/items

Will have to investigate later to see what might be the problem.

[slorber]

Thanks for giving it a try.

For now I'm going to close all the pending PRs trying to solve this issue, see https://github.com/facebook/docusaurus/issues/8370#issuecomment-1500129085