ci: add new npm ci installer

1 files changed, 60 insertions, 0 deletions

diff --git a/doc/cli/npm-ci.md b/doc/cli/npm-ci.md
new file mode 100644
index 000000000..87e8d7907
--- /dev/null
+++ b/doc/cli/npm-ci.md
@@ -0,0 +1,60 @@
+npm-ci(1) -- Install a project with a clean slate
+===================================
+
+## SYNOPSIS
+
+    npm ci
+
+## EXAMPLE
+
+Make sure you have a package-lock and an up-to-date install:
+
+```
+$ cd ./my/npm/project
+$ npm install
+added 154 packages in 10s
+$ ls | grep package-lock
+```
+
+Run `npm ci` in that project
+
+```
+$ npm ci
+added 154 packages in 5s
+```
+
+Configure Travis to build using `npm ci` instead of `npm install`:
+
+```
+# .travis.yml
+install:
+- npm ci
+# keep the npm cache around to speed up installs
+cache:
+  directories:
+  - "$HOME/.npm"
+```
+
+## DESCRIPTION
+
+This command is similar to `npm-install(1)`, except it's meant to be used in
+automated environments such as test platforms, continuous integration, and
+deployment. It can be significantly faster than a regular npm install by
+skipping certain user-oriented features. It is also more strict than a regular
+install, which can help catch errors or inconsistencies caused by the
+incrementally-installed local environments of most npm users.
+
+Concretely, the main differences between an `npm install` call and an `npm ci`
+call are:
+
+* The resulting `node_modules/` is not meant for interactive development.
+* The project **must** have an existing `package-lock.json` or `npm-shrinkwrap.json`.
+* If dependencies in the package lock do not match those in `package.json`, `npm ci` will exit with an error, instead of updating the package lock.
+* `npm ci` can only install entire projects at a time: individual dependencies cannot be added with this command.
+* If a `node_modules` is already present, it will be automatically removed before `npm ci` begins its install.
+* It will never write to `package.json` or any of the package-locks: installs are essentially frozen.
+
+## SEE ALSO
+
+* npm-install(1)
+* npm-package-locks(5)