JSONL Viewer

Preview a formatted, syntax-highlighted view of any row in a .jsonl / .ndjson file — without copying it into a separate file.

Install Locally

Package the extension as a .vsix and install it into VS Code:

npm install
npm install -g @vscode/vsce
vsce package
code --install-extension jsonl-viewer-0.0.1.vsix

Then reload VS Code. To update later, bump the version, re-run vsce package, and install the new .vsix.

Usage

1. Open a .jsonl or .ndjson file.
2. Place the cursor on the row you want to inspect.
3. Run JSONL: Preview Row via:
   • the keybinding Cmd+Alt+J (macOS) / Ctrl+Alt+J (Windows/Linux),
   • the {} icon in the editor title bar,
   • the editor right-click context menu, or
   • the Command Palette.

A read-only, pretty-printed view of the row opens beside the editor, with full JSON highlighting and folding. While the preview is open, it follows your cursor: moving to another row updates the preview automatically.

Rows that fail to parse show the parse error and the raw line so you can spot the problem.

Extension Settings

• jsonlViewer.followCursor (default true): automatically update the preview as the cursor moves between rows while the preview is open.

Development

• npm run compile — type-check, lint, and bundle.
• npm test — run tests.
• Press F5 to launch an Extension Development Host; open sample.jsonl to try it out.