📦 jq-lite

A lightweight CLI tool built in Rust for querying JSON data using simple dot notation.

🚀 Current Features

• ✅ Read JSON from a file
• ✅ Query top-level fields
• ✅ Query nested JSON using dot notation
• ✅ Multiple queries in a single command (space-separated)
• ✅ Uses serde_json for parsing

📖 Usage

jq-lite <query> <file-path>

🧪 Examples

• Basic query

jq-lite "name" data.json

• Nested query

jq-lite "user.name" data.json

• Multiple queries

jq-lite "name age user.email" data.json

🛠️ How It Works

• Queries are split by whitespace
• Nested queries (user.name) are converted into JSON Pointer format:

user.name → /user/name

Uses

• Value::get() for top-level fields
• Value::pointer() for nested access

⚠️ Current Limitations

• ❌ No array indexing (users[0])
• ❌ No stdin support
• ❌ No pretty printing
• ❌ Basic error handling
• ❌ No query validation
• ❌ No support for pipes or filters
• ❌ Not streaming (loads full JSON into memory)

Recent Addons

1. Add stdin support for JSON input

   Allow piping JSON into jq-lite:

   cat data.json | jq-lite "name"
   

2. Support raw JSON string as input

   Allow users to pass JSON directly instead of file path:

   jq-lite "name" '{"name":"John"}'
   

3. Improve CLI argument validation

   • Handle missing arguments
   • Show usage instructions
   • Prevent panics on missing inputs

4. Add --help flag

   Display usage, examples, and available options

5. Support array indexing in queries

   jq-lite "users[0].name" data.json
   

6. Support wildcard array queries

   jq-lite "users[].name" data.json
   

7. Refactor query parsing logic Replace simple .split(".") with a proper parser to support:

   • Arrays
   • Future filters
   • Better extensibility

8. Validate query syntax before execution

   Return meaningful errors for invalid queries

9. Add --pretty flag for formatted output

   Pretty-print JSON results

10. Add --compact flag

    Return minified JSON output

11. Add --raw flag

    Print raw values without JSON quotes

12. Improve error handling and messaging

    • File not found
    • Invalid JSON
    • Missing fields
    • Invalid queries

13. Add strict mode for query failures

    • Fail when a query returns no result
    • Return non-zero exit code

14. Add unit tests

• Nested queries
• Missing fields
• Invalid JSON

15. Add CLI integration tests

    Test full command execution

🧭 Roadmap (GitHub Issues)

⚡ Performance & Architecture

16. Optimize memory usage in query parsing

    Avoid unnecessary allocations and cloning

17. Implement query AST (Abstract Syntax Tree)

    Example:

    users[0].name → Field("users") → Index(0) → Field("name")
    

18. Add streaming JSON parsing

    Handle large JSON files without loading entire file into memory

💡 Future Enhancements (Stretch Goals)

19. Support pipe operator (|)

jq-lite "users | name" data.json

20. Add simple filtering support

jq-lite "users[?age>18]" data.json

21. Add interactive REPL mode

jq-lite
> user.name

🏗️ Building

cargo build --release

📄 License

MIT

🤝 Contributing

Contributions are welcome. Please open an issue before submitting a PR.