Do yarn workspaces work with npm, too?

npm has plans to implement workspaces somewhere along the v7, hopefully. They've written about it in their blog and there's an accepted proposal.

Managing dependencies in a monorepo is not supported with npm. The Lerna package is used to manage JavaScript projects with cross dependencies. I believe Lerna uses Yarn under the hood, but with Yarn as your project's package manager, this feature is supported out of the box.

Here is a repo that might be helpful to see how Yarn and Lerna work together: https://github.com/Quramy/lerna-yarn-workspaces-example

Now that npm v7.0.0 is out, npm supports workspaces. You can manage multiple packages from within a singular top-level, root package. See more at https://github.blog/2020-10-13-presenting-v7-0-0-of-the-npm-cli/

Your workflows will not get npm v7.0.0 by default unless you install it using npm install -g npm@7.