tldr calls: JavaScript call graph always returns empty (missing language handler)

[tnakamura2026]

Summary

tldr calls returns an empty call graph for JavaScript projects, and crashes when a file path (instead of directory) is passed.

Environment

• tldr version: 1.5.2
• Project type: Node.js/Express backend (.js, .cjs, .mjs files)

Bug 1: JavaScript call graph not implemented (silent empty result)

Steps to reproduce

tldr calls /path/to/js-project --lang javascript
# Returns: {"edges": [], "count": 0}

Even without --lang, auto detection on a JS project returns javascript as the first language, so the same empty result occurs.

Root cause

In cross_file_calls.py, build_project_call_graph() has branches for python, typescript, go, rust, java, c, php — but no branch for javascript:

# cross_file_calls.py ~L3300
if language == "python":
    _build_python_call_graph(...)
elif language == "typescript":
    _build_typescript_call_graph(...)
elif language == "go":
    ...
# ← javascript is missing!

Meanwhile, scan_project() already supports javascript correctly (.js, .jsx, .mjs, .cjs). Only the call graph builder is missing.

Expected behavior

tldr calls should work for JavaScript projects, similar to TypeScript.

Suggested fix

Add a _build_javascript_call_graph() function (or reuse _build_typescript_call_graph with a language parameter), and add the missing branch:

elif language == "javascript":
    _build_javascript_call_graph(root, graph, func_index, workspace_config)

---

Bug 2: Crash when file path passed instead of directory

Steps to reproduce

tldr calls /path/to/backend/index.js
# Error: [Errno 20] Not a directory: '/path/to/backend/index.js/.tldr/cache'

Root cause

In cli.py, _get_or_build_graph() does not validate that the path is a directory:

# cli.py ~L476
project = Path(project_path).resolve()
cache_dir = project / ".tldr" / "cache"   # tries to treat file as dir
cache_dir.mkdir(parents=True, exist_ok=True)  # → [Errno 20] Not a directory

Suggested fix

Add directory validation at the start of the calls command handler:

elif args.command == "calls":
    if not Path(args.path).is_dir():
        print(f"Error: '{args.path}' is not a directory", file=sys.stderr)
        sys.exit(1)
    ...

---

Workaround

Until fixed, use structure + imports as alternatives:

tldr structure /path/to/backend --lang javascript
tldr imports /path/to/backend/index.js

Or use --lang typescript if the project has .ts files.