Juxta

Juxta (from juxtapose — to place side by side) is a desktop file & folder comparison and merge tool built with Electron + React + TypeScript — a Beyond Compare–style clone. Compare folders, files, images, documents, archives, tables and structured data; merge and sync changes; and drive it from git, the Explorer context menu, or the command line.

Grab the latest Windows build from the Releases page:

• Juxta Setup (installer) — installs to Program Files, adds Start Menu/Desktop shortcuts and the Explorer context menu.
• Juxta Portable — no installation, just run it.

Open a tab from the + menu (Folder / File / Text / 3-Way Folders):

• Folder compare — synchronized two-pane tree, color-coded identical / different / left-only / right-only with a newer marker, moved/renamed detection, and a per-directory churn heatmap. Merge actions: copy ←/→, delete orphans, one-click make folders match, and sync (mirror / update / two-way) with a dry-run preview. A filter box above the tree narrows it to files whose name matches as you type, and the status-bar count chips (different / left-only / right-only) are clickable to hide/show each category.
• File compare — the comparator is auto-detected from the file types:
  • images (png/jpg/gif/webp…) → side-by-side, opacity overlay, swipe, and pixel-diff heatmap
  • PDF & Office (pdf/docx/xlsx/pptx) → extracted-text diff
  • archives (zip/jar/tar/tgz/tar.gz) → content-tree compare; double-click an entry to diff it
  • tables (csv/tsv) → key-column-aligned row/cell compare
  • structured (json/yaml/xml) → key-aligned tree; js/ts (+jsx/tsx) & lua → text ⇄ AST toggle
  • anything else → Monaco text diff (or hex for binary; a windowed hex viewer for huge files)
• Text compare — two editable panes; paste and diff live, copy sections across, apply a patch. A ¶ Whitespace toggle (in the file/text diff toolbars) renders tabs & spaces as visible glyphs.
• 3-Way Folders — base / left / right classification (modified/added/deleted/conflict); double-click a file to resolve it in the 3-way merge view.

The + (new session) menu also lists your recent folder/file comparisons for one-click re-open.

Glob include/exclude, ignore whitespace / case / blank lines, ignore-lines-by-regex, and format-aware compare for JSON / YAML / XML / CSV and JS/TS (AST). Bind whitespace/case/blank overrides to file globs with per-file-type rules, save named profiles, and pin options to a specific folder pair. Comparison rule: content (SHA-1), size+timestamp, or quick (size only).

• Snapshots — capture a folder to a .juxtasnap file and later compare a live folder (or another snapshot) against it offline.
• Reports — export a folder comparison as HTML or CSV.
• Patches — copy / save a unified diff, or apply a .patch in the text compare.

• Git difftool / mergetool — the menu's Git setup copies the git config commands. Then: git difftool opens pairs in Juxta; git mergetool opens the 3-way merge (save MERGED, then answer git's "was the merge successful?" prompt).
• Explorer context menu (installed build) — right-click "Juxta: Select Left" on one item, then "Compare with Selected" on another (files or folders).
• FTP/FTPS — put an ftp://[user@]host/path URL on a Folder Compare side; Juxta mirrors it to a temp folder and compares. You're prompted for the password (not saved).
• Format converters — teach Juxta to text-compare file types it doesn't natively handle by mapping an extension to an external command that emits plain text on stdout (same trust model as a git difftool — you configure the command; it's spawned directly, no shell). Add entries to converters in the settings file (%APPDATA%/juxta/juxta-settings.json), e.g.:

  "converters": [
    { "name": "RTF", "extensions": ["rtf"], "command": "unrtf", "args": ["--text", "${file}"] }
  ]

  A matching pair then opens in a read-only extracted-text diff. Built-in comparators (image/PDF/Office/table/structured) still take precedence; converters handle the rest.
• CLI — headless folder compare:

  Juxta --cli <left> <right> [--out report.html|.csv] [--method content|sizeAndTime|quick] \
        [--include a,b] [--exclude a,b] [--verbose|-v] [--quiet|-q]
  

  Output: a human-readable summary by default; --verbose also lists every changed file (~ different · < left-only · > right-only); --quiet prints just the compact machine-readable line (different=… leftOnly=… …) for scripts. Exit code: 0 identical · 1 differences · 2 error. On packaged Windows use --out and the exit code (a GUI-subsystem exe has no attached console).

npm install      # install dependencies
npm run dev      # launch with hot reload (electron-vite)
npm test         # run the unit tests (vitest)
npm run typecheck
npm run build    # production build into out/
npm start        # preview the production build

Requires Node 18+.

npm run dist:win   # NSIS installer + portable .exe (x64) in release/
npm run dist:dir   # unpacked app folder only (release/win-unpacked/Juxta.exe)

Signing is disabled (win.signAndEditExecutable: false) so it builds without a certificate — the unsigned exe triggers a SmartScreen prompt on first run (More info → Run anyway). To ship signed binaries, provide CSC_LINK / CSC_KEY_PASSWORD and remove that flag.

Four layers with a strict rule — core and shared never import Electron:

• src/core/ — pure Node comparison engine (walk, hash, filters, encoding, hex, canonicalizers, archive/tar/office readers, merge). Unit-tested directly.
• src/shared/ — pure TS shared by all layers incl. the renderer (IPC contract, types, diff/merge math, sync/snapshot/table/structured/AST helpers).
• src/main/ — Electron main (window, IPC, single-instance, git/CLI/shell launch); comparison runs in a worker thread with a persistent hash cache.
• src/preload/ — contextBridge exposing window.api.
• src/renderer/ — React UI.

See CLAUDE.md for contributor details and FEATURES.md for the feature matrix.