Codemirror blob: Scroll search match into view

[fkling]

Addresses #42482

This commit adds logic to scroll the next occurrence of the blob search term into view if no match is present in the current viewport.

It doesn't look like CodeMirror provides an API to actually "select" a specific match. An alternative approach would be to just determine whether any match is visible and then call findNext to actually select the next match, but I'm actually not sure how deterministic it is.

cm-blob-scroll-match.mp4

Test plan

• Go to any file (e.g. github.com/sourcegraph/sourcegraph/-/blob/doc/dev/background-information/web/temporary_settings.md?view=code)
• Search for a term that is present in the document, after the currently visible content -> next occurrence is scrolled into view.
• Search for a term that is present in the document, before the currently visible content -> first occurrence should be scrolled into view
• Search for a term that is not present in the document -> nothing should happen

App preview:

• Web
• Storybook

Check out the client app preview documentation to learn more.

[olafurpg]

LGTM 👍🏻 I didn't understand first what exactly this PR changes from the old behavior. Just to be 100% sure I got it right, the concrete difference is that you no longer have to press 'Enter' to focus on the first result?

[fkling]

@olafurpg

Just to be 100% sure I got it right, the concrete difference is that you no longer have to press 'Enter' to focus on the first result?

Yes, that's right. The first/next match will be scrolled into view as you type. At least that's how I understood the issue.