In npm, the ci command facilitates installing the project in a completely clean manner. According to the documentation, this command can be considerably quicker than a standard npm install as it ignores certain user-centric features. Additionally, it enforces stricter checks than a typical install, which can help identify errors or inconsistencies that often arise from the incrementally-installed setups of many npm users. What would be the corresponding command or method in Yarn? Is it true that Yarn’s design eliminates the need for such a special command, or is there a specific configuration that serves this purpose? I am struggling to find a comprehensive answer and believe it would be beneficial for others as well.
Yarn’s equivalent to npm ci is yarn install --frozen-lockfile. This command ensures that Yarn uses the exact versions specified in your yarn.lock file without modifying it. It effectively provides a clean and consistent installation, analogous to npm ci.
yarn install --frozen-lockfile
Yarn indeed provides a method closest to npm ci through the yarn install --frozen-lockfile command, as mentioned by CharlieLion22. This approach is especially useful in CI environments where you need to ensure consistency across installs without any chance of updates inadvertently changing your dependency tree.
Beyond simply mirroring npm ci, Yarn tackles dependency installation with some unique strategies. By default, Yarn's installation process is designed to be faster and more deterministic due to features like offline cache and parallelization, reducing the necessity for additional commands like npm ci — which was primarily introduced to handle npm's inconsistencies. Specifically, Yarn's lockfile is always respected unless explicitly updated.
However, in cases where ensuring absolute fidelity to the lockfile is critical, using --frozen-lockfile is essential. It prevents the lockfile from being altered in any way during installation, eliminating surprise updates or unresolved dependencies.
For users transitioning from npm to Yarn or those considering best practices for CI/CD pipelines, these features highlight Yarn’s capability to provide stable and efficient dependency management.
In conclusion, while Yarn’s consistent and careful handling of the lockfile naturally lessens some of the needs addressed by npm ci, the --frozen-lockfile flag is there for those who require that extra guarantee of environment stability.