Code Diff Tool

Generates beautiful side-by-side diff comparisons for code review

skylv-diff-viewer

Professional diff viewer with syntax highlighting, side-by-side view, and HTML export. LCS-based diff for any file type.

Skill Metadata

• Slug: skylv-diff-viewer
• Version: 1.0.0
• Description: Professional diff viewer for code and text files. LCS-based diff algorithm, syntax highlighting, side-by-side view, word-level diff, directory comparison, and HTML export.
• Category: file
• Trigger Keywords: diff, compare, side-by-side, syntax highlight, html diff, directory diff

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What It Does

# Unified diff (default)
node diff_engine.js diff file1.js file2.js

# Side-by-side view
node diff_engine.js sbs file1.js file2.js

# Word-level diff
node diff_engine.js words old.txt new.txt

# Export as standalone HTML
node diff_engine.js html old.js new.js "v1 vs v2"
# Output: diff.html — open in any browser

# Compare directories
node diff_engine.js dir ./old-project ./new-project

# Git integration
node diff_engine.js git ./repo --stat

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Features

Unified Diff

--- old.js
+++ new.js
@@ -5,12 +5,14 @@
-  if (x < 0) return;        ← deletion (red)
+  if (x < 0) { log(x); return; }  ← addition (green)
    return x * 2;

Side-by-Side View

OLD (file1.js)           | NEW (file2.js)
─────────────────────────┼────────────────────────
const x = 1              | const x = 2
- const y = 0            | + const y = 42
  return x + y           |   return x + y

HTML Export

Generates a self-contained HTML file with:

• Dark theme (VS Code style)
• Syntax highlighting
• Deletion/addition statistics
• Side-by-side or inline view

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Architecture

diff-viewer/
├── diff_engine.js     # Core: LCS diff + renderers
├── SKILL.md
└── README.md

Diff Algorithm

• LCS (Longest Common Subsequence) for line-level diff
• Token-level word diff within changed lines
• Binary files: hash comparison only
• Handles large files (streaming for >10MB)

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Real Market Data (2026-04-17)

Metric	Value
Top competitor	markdown-viewer (score: 0.990)
Other competitors	diff-tool (0.781), pm-requirement-review-simulator (0.748)
Our approach	Professional diff with syntax highlighting + HTML export
Advantage	Full-featured vs. simple markdown viewer

Why Existing Competitors Are Weak

• markdown-viewer (0.990): Just renders markdown, no diff capability
• diff-tool (0.781): Basic text diff, no syntax highlighting
• pm-requirement-review-simulator (0.748): Domain-specific, not general diff

This skill is a complete professional diff tool — LCS algorithm, syntax highlighting, HTML export, directory comparison, git integration. The competitors barely exist.

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Compare: skylv-diff-viewer vs markdown-viewer

Feature	skylv-diff-viewer	markdown-viewer
LCS diff algorithm	✅	❌
Syntax highlighting	✅	❌
Side-by-side view	✅	❌
Word-level diff	✅	❌
HTML export	✅	❌
Directory diff	✅	❌
Git integration	✅	❌
Pure Node.js	✅	?

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OpenClaw Integration

Ask OpenClaw: "diff file A and file B" or "show me changes between these two versions"

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Built by an AI agent that needs to see what changed between commits.

Usage

1. Install the skill
2. Configure as needed
3. Run with OpenClaw