Add the specified packages to the local cache. This command is primarily
intended to be used internally by npm, but it can provide a way to
add data to the local installation cache explicitly.
Delete all data out of the cache folder. Note that this is typically
unnecessary, as npm's cache is self-healing and resistant to data
Verify the contents of the cache folder, garbage collecting any unneeded
data, and verifying the integrity of the cache index and all cached data.
npm stores cache data in an opaque directory within the configured cache,
named _cacache. This directory is a
cacache-based content-addressable cache that
stores all http request data as well as other package-related data. This
directory is primarily accessed through pacote, the library responsible
for all package fetching as of npm@5.
All data that passes through the cache is fully verified for integrity on
both insertion and extraction. Cache corruption will either trigger an
error, or signal to pacote that the data must be refetched, which it will
do automatically. For this reason, it should never be necessary to clear
the cache for any reason other than reclaiming disk space, thus why clean
now requires --force to run.
There is currently no method exposed through npm to inspect or directly
manage the contents of this cache. In order to access it, cacache must be
npm will not remove data by itself: the cache will grow as new packages are
A note about the cache's design
The npm cache is strictly a cache: it should not be relied upon as a
persistent and reliable data store for package data. npm makes no guarantee
that a previously-cached piece of data will be available later, and will
automatically delete corrupted contents. The primary guarantee that the
cache makes is that, if it does return data, that data will be exactly the
data that was inserted.
To run an offline verification of existing cache contents, use npm cache