JSONata Validator Extension
A l### New: Editor Tab Selection
- Select any open editor tab as the JSON input source
- Select any open editor tab as the JSONata expression source
- Changes in selected files automatically update the playground results
- Only shows files that are actually open as tabs in VS Code
- Perfect for testing expressions against multiple data setseight VS Code extension for validating JSONata templates and providing an interactive playground for testing expressions. This extension provides real-time validation of JSONata expressions using the official JSONata library.
Features
- Real-time validation: Validates JSONata expressions as you type
- Interactive playground: Test JSONata expressions with live results (similar to try.jsonata.org)
- Precise error positioning: Highlights exact error locations with character-level accuracy
- Detailed error reporting: Shows exact error positions with JSONata error codes (e.g., S0201, S0203)
- Enhanced error messages: Includes expected vs. actual tokens for better debugging
- Multi-line expression support: Handles complex JSONata expressions spanning multiple lines with accurate line/character positioning
- Multiple file support: Works with
.jsonata files and detects JSONata expressions in JSON files
- Context menu commands: Right-click to validate documents or selections
- Configurable: Customize validation behavior through VS Code settings
- Lightweight: No language server required - everything runs locally using the official JSONata library
JSONata Playground
The extension includes an interactive playground for testing JSONata expressions:
Features
- Three-panel layout: JSON Input (left), JSONata Expression (top-right), Results (bottom-right)
- Real-time evaluation: See results as you type with error handling
- Runtime error detection: Catches both compilation and evaluation errors
- VS Code integration: Full editor experience with syntax highlighting
- Editor tab selection: Select any open editor tab as input source for JSON data or JSONata expressions
- Live updates: Automatically updates results when you edit selected source files
- Multiple data sources: Quickly switch between different JSON files or JSONata templates
How to Use
- Command Palette:
Ctrl+Shift+P → "Open JSONata Playground"
- With Selection: Select JSONata code → "Open JSONata Playground with Selection"
- Context Menu: Right-click in
.jsonata files
- From Active Editor: Use "Populate Playground from Active Editor" to automatically detect and load content
New: Editor Tab Selection
- Select any open editor tab as the JSON input source
- Select any open editor tab as the JSONata expression source
- Changes in selected files automatically update the playground results
- Perfect for testing expressions against multiple data sets
New: Session Share/Import 🔥
- Share sessions: Export your current playground state (JSON input, JSONata expression, and results) as a shareable JSON format
- Import sessions: Import shared sessions from clipboard or file to recreate the exact playground state
- One-click sharing: Copy session to clipboard or save to file with a single click
- Collaboration: Perfect for sharing examples, debugging, and team collaboration
- Automatic layout: Imported sessions automatically set up the 3-panel layout
- See SHARE-IMPORT-FEATURE.md for detailed documentation
See PLAYGROUND.md for detailed playground documentation and EDITOR-TAB-SELECTION.md for the new editor selection feature.
Validation Features
The extension provides comprehensive JSONata validation by leveraging the official JSONata parser:
Error Detection
- Syntax errors: Invalid JSONata syntax with precise error locations
- Missing brackets/parentheses: Detects unclosed
[, (, { with exact positions
- Invalid operators: Catches invalid operator usage like
.. double dots
- Function call errors: Validates function syntax and parameter structure
Error Reporting
- Error codes: Shows JSONata error codes (S0201, S0203, etc.)
- Character-level precision: Highlights exact characters where errors occur
- Helpful messages: "Expected ']', got '}'" style messages
- Token information: Shows actual vs. expected tokens
- Multi-line accuracy: Correctly positions errors across line boundaries
Expression Types Supported
- Simple property access:
$.firstName
- Array filtering:
$.products[price > 100]
- Complex transformations:
$.orders[status = "shipped"].{name: customer, total: total}
- Function calls:
$sum($.items.price)
- Multi-line expressions with proper bracket matching
Usage
File Types Supported
.jsonata files: Dedicated JSONata template files with full multi-line support- JSON files: Automatically detects JSONata expressions within JSON strings
Commands
- Validate JSONata Document: Validates the entire active document
- Validate JSONata Selection: Validates only the selected text
- Open JSONata Playground: Opens the interactive playground
- Open JSONata Playground with Selection: Opens playground with selected text as expression
- Populate Playground from Active Editor: Load content from current editor automatically
- Share Playground Session: Share current playground state as JSON 🆕
- Import Playground Session: Import a shared playground session 🆕
- Export Playground to Clipboard: Quick export to clipboard 🆕
- Import Playground from Clipboard: Quick import from clipboard 🆕
Access these commands via:
- Command Palette (
Ctrl+Shift+P / Cmd+Shift+P)
- Right-click context menu (when editing .jsonata files)
- Share/Import buttons in the playground results panel 🆕
Configuration
Configure the extension through VS Code settings:
{
"jsonataValidator.validateOnType": true, // Validate as you type
"jsonataValidator.validateOnSave": true, // Validate when saving
"jsonataValidator.maxNumberOfProblems": 100 // Maximum errors to show
}
Examples
Valid JSONata Expressions
$.firstName
$.address.city
$.products[price > 100]
$.orders[status = "shipped"].total ~> $sum()
// Multi-line expressions
$.products[
price > 100 and
category = "electronics"
].{
"name": name,
"discountedPrice": price * 0.9
}
Error Examples with Improved Reporting
// Error S0201: Syntax error: ".."
$.firstName..invalid
// Error S0203: Expected "]" before end of expression
$.products[price > 100
// Error S0202: Expected ")", got "syntax"
$count(invalid syntax here
// Error S0203: Expected "}" before end of expression
$.{unclosed: "object"
The extension now shows:
- Error codes (S0201, S0203, etc.)
- Exact positions where errors occur
- Expected vs. actual tokens for clearer debugging
Development
To build and run the extension locally:
npm install
npm run compile
Press F5 in VS Code to launch the extension in a new Extension Development Host window.
Contributing
- Fork the repository
- Create a feature branch
- Make your changes
- Test thoroughly
- Submit a pull request
License
MIT License - see LICENSE file for details.
