spyglass Documentation

Visualize, analyze, and debug your dependency trees. spyglass shows npm download counts, disk usage, outdated packages, circular deps, and unused dependencies — all from a single CLI command with no runtime dependencies.

CLI Commands

Full reference for graph, circular, unused, and why commands.

Library API

Import spyglass programmatically — parseGraph, findCircular, findUnused, why.

Features

npm Registry Data

Fetches weekly download counts, latest versions, and descriptions from the npm registry for every dependency.

Disk Size Analysis

Shows how much disk space each package consumes in node_modules, plus a total at the end.

Outdated Detection

Compiles local version against npm latest and flags outdated packages inline in the tree.

Dependency Tracing

Use `why` to trace why a specific package is in your tree — shows the full resolution path.

Zero Runtime Deps

The CLI is a standalone script with no runtime dependencies — install once and run anywhere.

Monorepo Support

Use `--path` to analyze any sub-package. Works with npm, yarn, pnpm, and bun workspaces.