How to sync `yarn.lock` with `package.json`?

Question

I installed a package with yarn add --dev, run its setup process and during it, the package installed several other packages and added those to package.js

Answer 1

Run yarn install, or just yarn.

The lock file is updated in its entirety on any change to dependencies, i.e. when you run a yarn command.

From the Yarn docs:

Your yarn.lock file is auto-generated and should be handled entirely by Yarn. As you add/upgrade/remove dependencies with the Yarn CLI, it will automatically update your yarn.lock file. Do not edit this file directly as it is easy to break something.

(Emphasis my own)