hone-editor

Package: @honeide/editor — embeddable code editor. 353 tests.

cd hone-editor && bun test

The editor is structured in three layers: core (platform-independent logic), view-model (reactive state bridge), and native (Rust FFI per platform).

Core

buffer/

Piece table backed by a rope with a line index. TextBuffer wraps rope internals with a clean API for editing and querying.

cursor/

Multi-cursor management. CursorManager handles primary and secondary cursors with merging, sorting, selection ranges, and word boundary detection.

history/

UndoManager with time-based coalescing (500ms window, max depth 10000). Each operation records: edits, deleted texts, cursor state before and after. Supports computeInverseEdits for redo.

viewport/

ViewportManager for virtual scrolling. Computes visible line range with a 10-line buffer zone. Tracks hidden lines from code folding. Includes ScrollController and LineHeightCache.

tokenizer/

SyntaxEngine via Lezer parser integration. Incremental tokenization — only re-tokenizes affected regions after edits. Token theme resolution maps parser tokens to editor colors. KeywordSyntaxEngine serves as a fallback when no grammar is available.

Bundled grammars: TypeScript, HTML, CSS, JSON, Markdown, Python, Rust, C++

search/

SearchEngine supporting literal and regex modes, chunked for large files. Replace supports regex capture group expansion. IncrementalSearch powers the live find widget.

folding/

Two folding strategies:

• Indent-based — fallback for languages without a grammar
• Syntax-based — uses Lezer parse tree

FoldState tracks collapsed ranges.

diff/

Myers diff algorithm with O(ND) complexity. DiffResult contains hunks typed as add, delete, or modify. Utilities: mergeAdjacentHunks, splitHunk, navigateHunks. Supports inline character-level diff within hunks.

document/

EditorDocument combines TextBuffer with metadata: URI, languageId, version, isDirty, encoding, and line-ending detection. EditBuilder provides a transaction API for batching edits.

commands/

CommandRegistry maps string IDs to handler functions. Five command modules:

1. Editing (insert, delete, indent)
2. Navigation (move, scroll, go-to)
3. Selection (select word, line, all)
4. Clipboard (cut, copy, paste)
5. Multicursor (add cursor above/below, select occurrences)

lsp-client/

LSPClient wrapping JSON-RPC transport. Typed methods for completion, hover, diagnostics, and code actions. Manages the initialize/initialized lifecycle. ServerCapabilityChecker queries what the server supports.

dap-client/

DAPClient for debug sessions. Supports launch/attach configurations, breakpoint management, stepping (into/over/out), stack frame inspection, and variable evaluation.

snippets/

Snippet template processing with tab stops, placeholders, and variable expansion. Language-specific snippet registries.

View-Model

Reactive state bridge between core subsystems and rendering.

EditorViewModel is the main orchestrator. It connects buffer, cursor, viewport, tokenizer, search, and folding into a unified state that the native layer consumes.

Sub-models:

Native (Rust FFI)

NativeEditorFFI interface defines 93+ FFI functions covering rendering, input handling, events, font metrics, and color management.

Key components:

• NativeRenderCoordinator — orchestrates rendering calls to the platform layer
• TouchInputHandler — processes touch events for mobile platforms
• Word wrap computation

Six platform crates: