jj-diff

jj-diff

A fast, keyboard-driven TUI for viewing and manipulating diffs in Jujutsu (jj). Move changes between commits, split commits interactively, or use as a drop-in replacement for jj's builtin diff editor.

Features

• Browse Mode: View diffs with syntax highlighting, search, and fuzzy file finding
• Interactive Mode: Select and move hunks or individual lines between revisions
• Diff-Editor Mode: Use with jj split, jj diffedit, jj amend -i, jj squash -i
• Multi-Split Mode: Tag changes and split commits into multiple focused commits
• Fast: Handles 5000+ files and 20K+ line diffs instantly
• Beautiful: Catppuccin themes with syntax highlighting for 100+ languages

Installation

# Build from source
mise install && hk install --mise
mise run build

# Or install with go
go install github.com/kyleking/jj-diff/cmd/jj-diff@latest

Quick Start

Browse Diffs

View and search through changes:

# View working copy changes
jj-diff

# View specific revision
jj-diff -r @-

# Search with '/', fuzzy find with 'f'

Move Changes Between Commits

Interactively select hunks or lines to move:

jj-diff --interactive

# Press 'd' to select destination
# Press Space to select hunks
# Press 'v' for line-level selection
# Press 'a' to apply changes

Use as jj's Diff-Editor

Replace jj's builtin editor:

# ~/.config/jj/config.toml
[ui]
diff-editor = "jj-diff"
diff-instructions = false

Then use with jj commands:

jj split          # Split current commit
jj diffedit       # Edit changes in commit
jj amend -i       # Amend interactively
jj squash -i      # Squash interactively

Split Commits into Multiple Parts

Tag changes and create focused commits:

jj-diff --interactive

# Press 'S' to enter multi-split mode
# Tag hunks with 'a', 'b', 'c', etc.
# Press 'D' to assign tags to commits
# Press 'P' to preview and apply

Keybindings

Press ? for help overlay with all keybindings.

Essential Keys

Interactive Mode

Multi-Split Mode

Visual Indicators

• > Current hunk/line
• [X] Selected hunk
• [A] Tagged hunk (multi-split)
• █ Visual selection range
• • Selected line

Common Workflows

Move a Few Lines to Previous Commit

jj-diff --interactive
# Press 'd', select @-, press Enter
# Navigate to desired hunk with 'n'
# Press 'v' to enter visual mode
# Select lines with 'j/k'
# Press Space to confirm selection
# Press 'a' to apply

Split a Large Commit into Focused Changes

jj-diff --interactive
# Press 'S' to enter multi-split mode
# Tag related changes: press 'a' on UI changes, 'b' on tests, etc.
# Press 'D' to open assignment modal
# Assign tags to existing commits or create new ones
# Press 'P' to preview and apply split

Review Changes Before Committing

# Browse mode (read-only)
jj-diff

# Use '/' to search for TODO comments
# Use 'f' to quickly jump between files
# Press Tab to focus diff and scroll with j/k

Edit a Commit Interactively

# Configure jj-diff as diff-editor first
jj diffedit -r @-

# Select changes to keep with Space
# Line-level editing with 'v'
# Press 'a' to save and exit

Performance

jj-diff is optimized for real-world use:

• Handles 5,000+ files instantly (7μs render time)
• 20,000+ line diffs with no lag (52μs render time)
• Search across 100K lines in 17ms
• Syntax highlighting for 100+ languages

Tested on large repositories with excellent responsiveness.

Contributing

See CONTRIBUTING.md for development setup, tasks, and the git workflow, and DESIGN.md for the architecture overview, patterns, and testing guide.

Troubleshooting

TUI rendering issues: Try setting TERM=xterm-256color

Performance issues: Disable syntax highlighting or use browse mode for very large diffs

jj integration fails: Ensure jj 0.9.0+ is installed and in PATH

License

MIT