Code Diff Viewer

A professional text comparison editor based on Monaco Editor providing advanced code difference viewing and editing capabilities. Supports syntax highlighting, side-by-side comparison, inline editing, and more, ideal for code review, version comparison, document proofreading, and precise text difference analysis.

Key Features

Monaco Editor Core

Powered by Visual Studio Code's editor core Monaco Editor, providing the same editing experience as VS Code. Supports:

• Intelligent code completion
• Syntax highlighting
• Code folding
• Multi-cursor editing
• Find and replace
• Keyboard shortcuts

VS Code users can start working seamlessly.

Side-by-Side Comparison Mode

Displays original and modified versions in left-right panes with highlighted differences:

• Red background: Deleted content
• Green background: Added content
• Yellow border: Modified lines
• Connection lines: Show correspondence relationships

Difference annotations are precise to character level, making it easy to spot subtle changes.

Bidirectional Editing

Unlike read-only diff viewers, this tool supports direct editing of both sides:

• Left original version is editable (originalEditable: true)
• Right modified version is editable
• Real-time difference annotation updates

Suitable for correcting errors or merging changes during comparison.

Difference Navigation

Provides quick navigation features:

• Previous/Next difference buttons
• Difference statistics overview
• Scrollbar minimap showing difference distribution

Quickly locate change positions in large files.

Inline Difference View

Supports switching to inline mode (renderSideBySide: false), displaying differences in single-column format to save screen space. Suitable for narrow screen devices or when context focus is needed.

Syntax Highlighting

Automatically recognizes multiple programming languages and file types:

• JavaScript/TypeScript
• HTML/CSS/SCSS
• Python/Java/C++
• JSON/YAML/XML
• Markdown
• SQL
• 100+ languages

Detects automatically based on file extension or content, providing accurate syntax coloring.

Use Cases

Code Review

Review Pull Requests or Merge Requests by comparing old and new code versions. Intuitively view modifications, identify potential issues, and provide improvement suggestions.

Version Control

View file changes in Git, SVN, or other version control systems. Compare differences between commits to understand code evolution history.

Document Proofreading

Compare different document versions to check if editorial changes meet expectations. Suitable for reviewing technical documentation, API docs, user manuals, etc.

Configuration File Comparison

Compare configuration files between development, testing, and production environments to ensure configuration consistency and avoid environment issues.

Data Migration Validation

When migrating SQL scripts, JSON data, CSV files, etc., compare source and target files to verify data integrity and accuracy.

Usage Examples

Compare Code Before and After Refactoring

Scenario: Refactoring a function, need to confirm logic consistency.

Steps:

1. Paste pre-refactoring code on the left
2. Paste post-refactoring code on the right
3. Observe green (added) and red (deleted) highlights
4. Use navigation buttons to check each difference
5. Confirm core logic unchanged, only code structure optimized

Resolve Merge Conflicts

Scenario: Git merge conflict, need manual resolution.

Steps:

1. Paste base version code on the left
2. Paste feature branch code on the right
3. Compare differences to understand conflict causes
4. Edit directly on the right, keeping needed changes
5. Delete conflict markers, generate final version

API Documentation Change Tracking

Scenario: API interface upgrade, compare old and new documentation.

Steps:

1. Paste old API documentation on the left (Markdown format)
2. Paste new API documentation on the right
3. View newly added interfaces (green annotations)
4. View removed interfaces (red annotations)
5. Record breaking changes, notify relevant developers

Keyboard Shortcuts

Common shortcuts (same as VS Code):

Editing Operations

• Ctrl/Cmd + Z: Undo
• Ctrl/Cmd + Shift + Z: Redo
• Ctrl/Cmd + C/V/X: Copy/Paste/Cut
• Ctrl/Cmd + F: Find
• Ctrl/Cmd + H: Replace
• Alt + Up/Down: Move line

Multi-Cursor

• Alt + Click: Add cursor
• Ctrl/Cmd + Alt + Up/Down: Add cursor above/below
• Ctrl/Cmd + D: Select next occurrence

Code Folding

• Ctrl/Cmd + Shift + [: Fold
• Ctrl/Cmd + Shift + ]: Unfold

Important Notes

Large File Performance

Comparing very large files (>1MB) may affect performance. Recommendations:

• Only compare necessary parts, delete irrelevant content
• Disable minimap to reduce rendering overhead
• Use modern browsers (Chrome, Edge) for better performance

Line Ending Differences

Windows (\r\n), Unix (\n), and Mac (\r) use different line endings, potentially causing entire files to appear red. Monaco Editor handles this automatically, but note whether actual differences are line ending inconsistencies.

Character Encoding

Ensure both files use the same character encoding (UTF-8 recommended) before comparison, otherwise garbled text or misjudged differences may occur.

Whitespace Characters

By default, displays differences in spaces and tabs. To ignore whitespace differences, manually adjust formatting after editing.

Comparison with Similar Tools

Compared to diffchecker.com, Beyond Compare, VS Code Diff Editor, and similar tools, this tool's features:

1. Based on Monaco Editor, professional editing experience
2. Supports bidirectional editing, not just viewing but also modifying
3. 100+ language syntax highlighting, comprehensive coverage
4. Pure browser operation, no software installation needed
5. Local data processing, privacy secured
6. Responsive layout, adapts to various screen sizes

Ideal for developers needing temporary code or text comparison with direct editing during the comparison process.