ReverseHighlight does not highlight Cyrillic characters correctly

[Augen2203]

Hi Algolia team 👋

I'm using @algolia/autocomplete-js together with these plugins:

• @algolia/autocomplete-plugin-query-suggestions
• @algolia/autocomplete-plugin-recent-searches

I've encountered an issue where highlighting with fails to wrap matched parts when using Cyrillic characters (e.g. Ukrainian or Russian). For Latin characters, everything works fine — matches are wrapped and highlighted as expected.

🧪 Observations

• Queries are correctly matched — verified in logs.
• However, <components.ReverseHighlight> doesn't wrap Cyrillic matches in highlighting tags.
• Replacing with <components.Highlight> resolves the issue.

✅ Temporary Workaround

// Before:
<components.ReverseHighlight hit={item} attribute="query" />

// replaced with:
<components.Highlight hit={item} attribute="query" />


<components.ReverseHighlight hit={item} attribute="label" />
// replaced with:
<components.Highlight hit={item} attribute="label" />

Expected Behavior
should correctly highlight substrings in Cyrillic scripts.

###💡 Possible Fix
It seems related to Unicode-aware string matching or regex. Enhancing ReverseHighlight to support non-Latin alphabets—or documenting that Highlight is preferred for such cases—would be valuable.

Thanks for maintaining Autocomplete — it’s a fantastic tool!

Sources:

autocomplete-plugin-query-suggestions

autocomplete-plugin-recent-searches

[Haroenv]

Do you have an exact string that highlights wrong? maybe could you add a failing test case so we can investigate what's going wrong?