Add getLoggers() to list loggers in a category tree

[Polqt]

Closes #62.

Right now there's no way to find out which loggers exist in a running program. If you're building something like a debug panel where users can toggle categories on and off, or you just want to sanity-check what logging is active, you have to already know every category name up front.

This adds getLoggers(), which walks the category tree from a given logger (or the root, by default) and returns every logger in that subtree, including the one you passed in, in depth-first order:

const all = getLoggers();          // the whole tree, from the root down
const mine = getLoggers("my-app"); // "my-app" and its descendants only

It also accepts a Logger, a category string, or a category array, same as getLogger().

One thing worth calling out (this came up in the discussion on #62): it only sees loggers that have actually been created via a getLogger() call somewhere in the program, not every category that's been set up through configure(). If a category is only reached lazily inside a function that hasn't run yet, it won't show up. That's documented in the docstring.

Testing

Added tests in logger.test.ts covering: a fresh/never-touched category, a multi-level subtree in depth-first order, identity with getLogger(), the no-argument default, an untouched descendant being correctly omitted, and dead WeakRef entries being skipped without being pruned from the tree.

Ran the Node test suite locally (pnpm test in packages/logtape) — all passing. I wasn't able to run deno check/deno lint/mise run check in my environment (no deno/mise install available), so it'd be good to have CI confirm those.

---

AI disclosure: This PR was written with assistance from Claude Code (claude-sonnet-5) — design discussion, implementation, and tests. I reviewed and tested everything locally before submitting. See Assisted-by trailers in the commit.

[codecov]

Codecov Report

❌ Patch coverage is 95.45455% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 85.93%. Comparing base (602e54c) to head (c2ff7e8).
⚠️ Report is 7 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
packages/logtape/src/logger.ts	95.23%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #207      +/-   ##
==========================================
- Coverage   86.00%   85.93%   -0.08%     
==========================================
  Files          70       71       +1     
  Lines       12980    13015      +35     
  Branches     2925     2939      +14     
==========================================
+ Hits        11164    11184      +20     
- Misses       1288     1297       +9     
- Partials      528      534       +6     

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[dahlia]

Thanks for your contribution.

Could you run mise run fmt for formatting?

Also, it would be great if this feature is documented in the VitePress docs (docs/).

[Polqt]

Thanks for the feedback!

• Added a "Listing loggers" section to docs/manual/categories.md.
• Added the PR number and my name to the changelog fragment: [[Question: is there a way to grab list of all 'registered' categories? #62], [Add getLoggers() to list loggers in a category tree #207] by Jepoy].
• I don't have deno/mise available in my current environment, so I couldn't run mise run fmt directly. I formatted the new code by hand to match the surrounding style (2-space indent, alphabetized exports) and the markdown by hand to match the style guide. If CI flags anything mise run fmt would've caught, let me know and I'll fix it.

Pushed as 490bdfd.

[dahlia]

The code is still not well-formatted!

[dahlia]

This feature will be shipped with the next minor release, LogTape 2.4.0. Meanwhile, you could try v2.4.0-dev.865+57354081, a pre-release build.