How to install packages based on the lock-file with Yarn?

Yarn 1

I think your best bet is using the --frozen-lockfile flag with yarn install.


If you need reproducible dependencies, which is usually the case with the continuous integration systems, you should pass –frozen-lockfile flag.


Don’t generate a yarn.lock lockfile and fail if an update is needed.


If using yarn2 (aka yarn berry) this flag is renamed to --immutable as of v2.0.0.

From the docs

If the --immutable option is set (defaults to true on CI since v3.0.0), Yarn will abort with an error exit code if the lockfile was to be modified. For backward compatibility we offer an alias under the name of --frozen-lockfile, but it will be removed in a later release.

This way if someone tries to push changes to package.json, say upgrade react from ^16.8.0 to ^16.10.0, without updating the yarn.lock file. Then it will error out in the CI like below.

> yarn install --frozen-lockfile
error Your lockfile needs to be updated, but yarn was run with `--frozen-lockfile`.

To address your comment:

I think that with yarn install the lock gets updated too often and the file loses its point since it actually does not lock versions. Or am I using the wrong commands?

Yarn/npm is just doing what you tell it to. If you set the version in your package.json to "react": "16.8.0" it will never update the yarn.lock but when using any of the npm ranges like the Caret (i.e. "react": "^16.8.0"), yarn/npm will resolve to the highest/newest version that satisfies the range you specified. You have all the power!


I found a small edge case. If you are running yarn add in your ci, such as for a ci only dependency, it will update the lock file and do an install for all dependencies. For example….

# Add ci dep
yarn add codecov

# Install all deps from yarn.lock
yarn install --frozen-lockfile

This will not error like you might expect. Instead, add the --frozen-lockfile to yarn add command like this…

# Add ci dep
yarn add codecov --frozen-lockfile

# Install all deps from yarn.lock
yarn install --frozen-lockfile

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