llnode

Why it's ranked here

The tool solves a narrow but difficult failure-analysis problem with unusually deep visibility. Its strongest case is postmortem diagnosis, where JavaScript frames, heap contents, references, and native state must be understood together. That value comes with substantial setup and compatibility constraints.

What's good

It combines JavaScript-aware inspection with the surrounding C++ debugger instead of separating the two worlds. Heap scans can group objects by type and size, locate instances, and search references by value, property, or string. Output controls cover source display, maps, full strings, array limits, detail levels, and pagination.

Tradeoffs

Installation requires LLDB and its development library, plus an officially distributed, currently active Node.js version. Distribution-provided Node.js builds may be incompatible. Core analysis also requires the exact executable that produced the dump. Windows needs additional build tooling, while Android and Termux support is explicitly experimental.

How to use it well

Use it when a Node.js crash, native package failure, or memory investigation demands both JavaScript and C++ context. Preserve each core dump with its matching Node.js executable, then inspect frames before narrowing into objects and references. It does not provide LLDB, a compatible Node.js build, or automatic crash-artifact collection.

Observed

License

MIT

Primary implementation

C++ plugin with a JavaScript packaging and addon layer

Install surface

Global npm package, optional Homebrew installation on macOS, and manual or system LLDB plugin loading

Interfaces

LLDB command plugin, command-line launcher, and optional Node-API addon

Platform support

macOS, Linux, FreeBSD, and Windows installation guidance; Android through Termux is experimental

Runtime requirements

LLDB is required, and supported Node.js builds must come from official channels

Testing structure

Separate Tape test commands exist for the LLDB plugin and Node addon