npm-ci — Install a project with a clean slate
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"
This command is similar to npm help install, except it's meant to be used in automated environments such as test platforms, continuous integration, and deployment -- or any situation where you want to make sure you're doing a clean install of your dependencies. 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.
In short, the main differences between using npm install and npm ci are:
- 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.
- npm help install
- npm help package-locks