npm(3) -- node package manager


var npm = require("npm")
npm.load([configObject, ]function (er, npm) {
  // use the npm object, now that it's loaded.

  npm.config.set(key, val)
  val = npm.config.get(key)

  console.log("prefix = %s", npm.prefix)

  npm.commands.install(["package"], cb)




This is the API documentation for npm. To find documentation of the command line client, see npm(1).

Prior to using npm's commands, npm.load() must be called. If you provide configObject as an object hash of top-level configs, they override the values stored in the various config locations. In the npm command line client, this set of configs is parsed from the command line options. Additional configuration params are loaded from two configuration files. See npm-config(1), npm-config(7), and npmrc(5) for more information.

After that, each of the functions are accessible in the commands object: npm.commands.<cmd>. See npm-index(7) for a list of all possible commands.

All commands on the command object take an array of positional argument strings. The last argument to any function is a callback. Some commands take other optional arguments.

Configs cannot currently be set on a per function basis, as each call to npm.config.set will change the value for all npm commands in that process.

To find API documentation for a specific command, run the npm apihelp command.


  • npm.load(configs, cb)

    Load the configuration params, and call the cb function once the globalconfig and userconfig files have been loaded as well, or on nextTick if they've already been loaded.

  • npm.config

    An object for accessing npm configuration parameters.

    • npm.config.get(key)
    • npm.config.set(key, val)
    • npm.config.del(key)
  • npm.dir or npm.root

    The node_modules directory where npm will operate.

  • npm.prefix

    The prefix where npm is operating. (Most often the current working directory.)

  • npm.cache

    The place where npm keeps JSON and tarballs it fetches from the registry (or uploads to the registry).

  • npm.tmp

    npm's temporary working directory.

  • npm.deref

    Get the "real" name for a command that has either an alias or abbreviation.


For each of the methods in the npm.commands hash, a method is added to the npm object, which takes a set of positional string arguments rather than an array and a callback.

If the last argument is a callback, then it will use the supplied callback. However, if no callback is provided, then it will print out the error or results.

For example, this would work in a node repl:

> npm = require("npm")
> npm.load()  // wait a sec...
> npm.install("dnode", "express")

Note that that won't work in a node program, since the install method will get called before the configuration load is completed.


In order to support npm ins foo instead of npm install foo, the npm.commands object has a set of abbreviations as well as the full method names. Use the npm.deref method to find the real name.

For example:

var cmd = npm.deref("unp") // cmd === "unpublish"