npm doctor runs a set of checks to ensure that your npm installation has
have some basic requirements that must be met:
registry.npmjs.com, or another service that uses
the registry API, is available.
node_modules (both locally and globally),
exist and can be written by the current user.
Without all of these working properly, npm may not work properly. Many issues
are often attributable to things that are outside npm's code base, so
doctor confirms that the npm installation is in a good state.
Also, in addition to this, there are also very many issue reports due to using
old versions of npm. Since npm is constantly improving, running
better than an old version.
npm doctor verifies the following items in your environment, and if there are
any recommended changes, it will display them.
By default, npm installs from the primary npm registry,
npm doctor hits a special ping endpoint within the registry. This can also be
npm ping. If this check fails, you may be using a proxy that
needs to be configured, or may need to talk to your IT staff to get access over
This check is done against whichever registry you've configured (you can see
what that is by running
npm config get registry), and if you're using a
private registry that doesn't support the
/whoami endpoint supported by the
primary registry, this check may fail.
While Node.js may come bundled with a particular version of npm, it's the
policy of the CLI team that we recommend all users run
npm@latest if they
can. As the CLI is maintained by a small team of contributors, there are only
resources for a single line of development, so npm's own long-term support
releases typically only receive critical security and regression fixes. The
team believes that the latest tested version of npm is almost always likely to
be the most functional and defect-free version of npm.
For most users, in most circumstances, the best version of Node will be the latest long-term support (LTS) release. Those of you who want access to new ECMAscript features or bleeding-edge changes to Node's standard library may be running a newer version, and some of you may be required to run an older version of Node because of enterprise change control policies. That's OK! But in general, the npm team recommends that most users run Node.js LTS.
Some of you may be installing from private package registries for your project
or company. That's great! Others of you may be following tutorials or
StackOverflow questions in an effort to troubleshoot problems you may be
having. Sometimes, this may entail changing the registry you're pointing at.
This part of
npm doctor just lets you, and maybe whoever's helping you with
support, know that you're not using the default registry.
While it's documented in the README, it may not be obvious that npm needs Git
installed to do many of the things that it does. Also, in some cases
– especially on Windows – you may have Git set up in such a way that it's not
accessible via your
PATH so that npm can find it. This check ensures that Git
node_modules path, if you're running
npm doctor with a project
directory, must be readable and writable by the user running npm.
When an npm package is published, the publishing process generates a checksum
that npm uses at install time to verify that the package didn't get corrupted
npm doctor uses these checksums to validate the package tarballs
in your local cache (you can see where that cache is located with
get cache, and see what's in that cache with
npm cache ls – probably more
than you were expecting!). In the event that there are corrupt packages in your
cache, you should probably run
npm cache clean and reset the cache.