IDML View

A minimal VS Code extension for browsing and editing the contents of Adobe InDesign .idml files that are already inside your workspace.

.idml files are ZIP-based UCF (Universal Container Format) containers holding a tree of XML parts (spreads, stories, styles, resources, designmap.xml, etc.). IDML View extracts one in place, right where the file was, so you can browse and edit those parts directly in the Explorer without manually unzipping anything — and repack your edits back into a valid .idml file when you're done.

Features

• Open — extracts an .idml file into a real folder at the exact same path, so it appears in the Explorer in the file's place. No virtual filesystem, no separate mount step.
• Browse and edit — the extracted contents are ordinary files on disk; open, edit, and save them like anything else in your workspace.
• Close, with a choice — discard your changes and restore the original file untouched, or repack the (possibly edited) contents back into a valid .idml file, preserving the UCF mimetype-first constraint IDML/InDesign requires.
• Validity check on open — warns if a file doesn't look like a properly-formed UCF container, so a later repack isn't a surprise.
• Custom file icon for .idml files, and a small badge on folders that are currently expanded.

Usage

1. Run IDML View: Open IDML Archive... from the Command Palette, or right-click a .idml file in the Explorer and choose it from the context menu.
2. The archive is extracted in place — the resulting folder takes over the original file's exact name, so it shows up in the Explorer right where the file was, with no visible marker. Expand it to browse the internal file tree; click any entry to open it in a normal editor.
3. To close it, right-click the folder in the Explorer (or run IDML View: Close IDML Archive from the Command Palette) and choose whether to preserve your changes:
   • No — discards the extracted folder and restores the original .idml file untouched.
   • Yes — repacks the extracted contents (including any edits) into a new .idml file in its place.

Scope

• Only .idml files already inside the current VS Code workspace are supported.
• If a file doesn't look like a valid UCF container (e.g. its mimetype entry isn't first, or isn't stored uncompressed), a warning is shown when it's opened. It can still be extracted and browsed.
• While an archive is open, the original .idml file is physically relocated into the extracted folder rather than merely hidden, so that closing doesn't depend on any state that could be lost across a window reload. This mechanism may change as the extension gets more real-world testing.

Installing

Not yet published to the Marketplace. Build and install locally:

npm install
npm run package             # produces idml-view-<version>.vsix

Then, in VS Code: Command Palette → Extensions: Install from VSIX... → select the generated .vsix file.

Development

• npm run compile — type-check and build.
• npm run watch — incremental build on change.
• npm run test:unit — run the unit test suite.
• Press F5 (with this folder open in VS Code) to launch an Extension Development Host for manual testing.

See CLAUDE.md for architecture notes.

License

Unlicense — public domain.