feat: add operator[] access support for TJValue

[njp2k5]

Description

Adds support for ergonomic json[key].as<T>() access syntax and uniform indexed access on TJValue.

This introduces:

• TJValue::as<T>() as an alias for get<T>()
• TJValue::operator[](const TJCHAR* key)
• TJValue::operator[](int index)
• lightweight accessor chaining support

Supported usage examples:

json["name"].as<std::string>();
json["user"]["age"].as<int>();
json[0].as<int>();

This implementation keeps the change minimal and localized to existing access behavior.

Fixes #44

New Package?

• No

Version Bump?

• No

Type of Change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• I added new unit tests to cover this change

Added focused tests for:

• key access with as<T>()
• array index access
• object index access
• missing-key exception behavior

All tests pass locally:

539 tests passed

Suggested Checklist:

• I have performed a self-review of my own code
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR introduces a chainable operator[] accessor API for TJValue to simplify JSON navigation by key and index, and adds tests validating the new behavior (including strict-mode missing-key throwing).

Changes:

• Added TJValueAccessor and TJValue::operator[] overloads for key/index access with chainable .as<T>().
• Added TJValue::as<T>() convenience alias for get<T>().
• Added unit tests covering key/index access and strict missing-key behavior.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
tests/testtinyjsonvaluesget.cpp	Adds tests for new operator[] / accessor chaining and strict-mode missing-key throwing.
src/TinyJSON.h	Adds TJValueAccessor, TJValue::operator[] overloads, and TJValue::as<T>().

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[FFMG]

Hi @njp2k5,

Thank you so much for taking the time to implement this and writing such thorough unit tests! I saw the automated review here as well, and I really appreciate the depth of the work you put into resolving #44.

Because this is a lightweight library, I want to avoid adding proxy accessor classes to keep the core footprint minimal. Your approach actually prompted me to jump in and implement a native operator[] design directly into the core types over in #46.

I'm going to close this one in favour of that lightweight approach, but I sincerely appreciate your initiative and contribution here!

[njp2k5]

Thanks for the thoughtful feedback and explanation!

That makes sense — keeping the library lightweight is definitely a reasonable design goal here. I appreciate you taking the time to review the implementation and explain the direction taken in #46.

Glad the tests and exploration were still useful, and I enjoyed working through the issue.