npm-ci

Synopsis#

Description#

This command is similar to npm 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.

The main differences between using npm install and npm ci are:

• The project must have an existing package-lock.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 package-lock.json: installs are essentially frozen.

NOTE: If you create your package-lock.json file by running npm install with flags that can affect the shape of your dependency tree, such as --legacy-peer-deps or --install-links, you must provide the same flags to npm ci or you are likely to encounter errors. An easy way to do this is to run, for example, npm config set legacy-peer-deps=true --location=project and commit the .npmrc file to your repo.

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 CI 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"

Configuration#

See Also#

• npm install
• package-lock.json