[FR] Add Built-in Spell Checker with Real-Time Suggestions to AppFlowy Editor

[PraveenDevamane]

Description

This feature introduces a complete Spell Checker system in the AppFlowy Editor, providing real-time spell checking, underline styling for misspelled words, and suggestion popups

Impact

Spell checking significantly reduces typos and improves clarity, leading to more polished and professional documents. This benefits anyone who uses AppFlowy for writing—students, professionals, researchers, and teams.

Additional Context

No response

[LucasXu0]

Hi @PraveenDevamane, what's your plan to integrate a spell checker into the project?

[PraveenDevamane]

Thank you for reviewing my feature request.

My proposed plan for implementing a real-time spell checker inside the AppFlowy Editor. I have already completed a working prototype in my local repository, and I can refine it to match AppFlowy’s architecture and coding standards.

Implementation Summary

1.Spell Checker Service
A small service that loads the dictionary, watches for text changes, waits briefly before checking (debounce), finds spelling mistakes, and sends the results back to the UI.

2.Word Scanning & Suggestions
It picks out words from the text, cleans them, checks if they exist in the dictionary, and if not, creates suggestions using a basic edit-distance check.

3.Visual Underlines
Misspelled words are shown with a red wavy underline and a light highlight using overlay widgets. The actual document text is not changed.

4.Hover Suggestion Menu
When the user hovers over an underlined word, a small popup appears with spelling suggestions. This popup sits above the editor and doesn’t affect typing.

5.Word Replacement
Clicking a suggestion replaces the wrong word using normal editor actions, so undo/redo and cursor behavior still work correctly.