npm explain <package-spec>

alias: why

This command will print the chain of dependencies causing a given package to be installed in the current project.

If one or more package specs are provided, then only packages matching one of the specifiers will have their relationships explained.

The package spec can also refer to a folder within ./node_modules

For example, running npm explain glob within npm's source tree will show:

glob@7.1.6
node_modules/glob
 glob@"^7.1.4" from the root project

glob@7.1.1 dev
node_modules/tacks/node_modules/glob
 glob@"^7.0.5" from rimraf@2.6.2
 node_modules/tacks/node_modules/rimraf
 rimraf@"^2.6.2" from tacks@1.3.0
 node_modules/tacks
 dev tacks@"^1.3.0" from the root project

To explain just the package residing at a specific folder, pass that as the argument to the command. This can be useful when trying to figure out exactly why a given dependency is being duplicated to satisfy conflicting version requirements within the project.

$ npm explain node_modules/nyc/node_modules/find-up
find-up@3.0.0 dev
node_modules/nyc/node_modules/find-up
 find-up@"^3.0.0" from nyc@14.1.1
 node_modules/nyc
 nyc@"^14.1.1" from tap@14.10.8
 node_modules/tap
 dev tap@"^14.10.8" from the root project

Whether or not to output JSON data, rather than the normal output.

Not supported by all npm commands.

Enable running a command in the context of the configured workspaces of the current project while filtering by running only the workspaces defined by this configuration option.

Valid values for the workspace config are either:

When set for the npm init command, this may be set to the folder of a workspace which does not yet exist, to create the folder and set it up as a brand new workspace within the project.

This value is not exported to the environment for child processes.