JSON Formatter (JSON/JSONC/JSONL)

VS Code extension to format JSON, JSONC, and JSONL/NDJSON for human-readability with consistent indentation and optional trailing newlines.

Why? Mainly for JSONL support. Existing VSCode JSON formatting extensions don't format JSONL well or don't validate it at all.

Features

• Formats JSON, JSONC, and JSONL (line-delimited JSON) into a neatly indented, human-readable layout.
• Works through the built-in Format Document action or the JSONExt: Format Document command.
• Respects jsonext.indentSize and jsonext.ensureFinalNewline settings for per-workspace control.

Usage

Open a JSON/JSONC/JSONL file and run Format Document, or invoke JSONExt: Format Document from the Command Palette.

Configuration

Configure indentation and trailing newline behavior via jsonext.indentSize and jsonext.ensureFinalNewline in your settings.

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Install via VSIX

1. Build or download the VSIX (a packaged jsonext-0.0.1.vsix lives at the repo root).
2. In VS Code, open the Command Palette and run Extensions: Install from VSIX..., then pick the VSIX file.
3. Alternatively, install from a terminal: code --install-extension /path/to/jsonext-0.0.1.vsix
4. Reload the window if prompted and the formatter will activate on JSON, JSONC, and JSONL files.

Development and Testing

• Install dependencies: npm install
• Build the extension: npm run compile
• Run the test suite (after compiling): npm test
• Watch for rebuilds during development: npm run watch
• Package a new VSIX: npm run package

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License: MIT

Copyright: © Mike Bijon @mbijon, 2025