The npm registry contains packages, many of which are also Node modules, or contain Node modules. Read on to understand how they differ and how they interact.
About packages
A package is a file or directory that is described by a package.json file. A package must contain a package.json file in order to be published to the npm registry. For more information on creating a package.json file, see "Creating a package.json file".
Packages can be unscoped or scoped to a user or organization, and scoped packages can be private or public. For more information, see
A package is any of the following:
- a) A folder containing a program described by a
package.json file.
- b) A gzipped tarball containing (a).
- c) A URL that resolves to (b).
- d) A
<name>@<version> that is published on the registry with (c).
- e) A
<name>@<tag> that points to (d).
- f) A
<name> that has a latest tag satisfying (e).
- g) A
git url that, when cloned, results in (a).
Git URLs used for npm packages can be formatted in the following ways:
git://github.com/user/project.git#commit-ishgit+ssh://user@hostname:project.git#commit-ishgit+http://user@hostname/project/blah.git#commit-ishgit+https://user@hostname/project/blah.git#commit-ish
The commit-ish can be any tag, sha, or branch that can be supplied as an argument to git checkout. The default commit-ish is master.
About modules
A module is any file or directory in the node_modules directory that can be loaded by the Node.js require() function.
To be loaded by the Node.js require() function, a module must be one of the following:
- A folder with a
package.json file containing a "main" field.
- A JavaScript file.
**Note:** Since modules are not required to have a `package.json` file, not all modules are packages. Only modules that have a `package.json` file are also packages.
In the context of a Node program, the module is also the thing that was loaded from a file. For example, in the following program:
var req = require('request')
we might say that "The variable req refers to the request module".