effective-dependency-tree

Forked from @automattic/effective-module-tree, hosted in https://github.com/Automattic/wp-calypso/tree/trunk/packages/effective-module-tree

effective-dependency-tree

CLI tool that generates an ASCII tree with the representation of packages in node_modules and their dependencies. This works over the actual node_modules files, so you need to install your dependencies first (i.e. npm install or yarn install).

It generates the logical representation of the tree. A package may appear multiple times if it is depended on by multiple packages, even if all point to the same file on the filesystem. In other words, it "un-hoists" hoisted/deduped packages.

It will traverse regular dependencies, devDependencies and peerDependencies, but will ignore optional peerDependencies (as specified in peerDependenciesMeeta).

Why?

Usually, the package manger has a way to list the dependencies (npm ls or yarn list). However this includes deduplicated packages, and requires the presence of the lock file to generate the tree. This is the package manager's vision of the tree.

System tools like ls, find or tree can generate a similar output, but those represent the filesystem view of the tree. Depending on how effective the package manager is hoisting dependencies, this view may not be comparable.

effective-dependency-tree generates node's vision of the dependency tree. Is what node will find when requiring dependencies, ignoring where the package physically live in the file system. This tree should be consistent across package managers and different hoisting capabilities. As such, it can be used to verify that the dependeny tree remains constant when migrating to a different package manager.

Usage

Run effective-dependency-tree in the root of your project.

Use effective-dependency-tree --root <path> to print the tree in a different project. Example:

effective-dependency-tree --root "./src/package.json"

This tool can generate either an ascii tree, or a list (easier to visualize dependency chains in big trees). It can be specified with the flags -o tree or -o list.

If you are using this tool to analyze many packages (e.g. in a monorepo), you can pass --root multiple times. Discovered trees will be reused and cached across packages, significatively speeding it up:

effective-dependency-tree --root "./packages/a/package.json" --root "./packages/b/package.json"

Check out effective-dependency-tree --help for other flags and examples.

Troubleshooting

Invoke the command with DEBUG=effective-dependency-tree ./effective-dependency-tree to get a verbose log of what is going on.