In my experience that’s simply not true.

We’ve seen more issues with Yarn in CI & prod than with npm 5.x

Both are great projects but npm is significantly more mature.

I guess it just depends on what you are doing. With npm 5.x installed packages started disappearing at random for me. Switched to yarn and no problems since.

I have never seen that (or even heard of it). How bizarre.

I've had it happen to me before. It's weird and annoying, and you basically have to nuke node_modules and sometimes package-lock.json, and then re-install everything to fix. That usually works.

https://github.com/npm/npm/issues/17929 and linked bugs.

Just out of curiosity, having never encountered any issues myself - what sort of issues have you run into with Yarn in CI/prod ?

Reliability, mostly. Also some strange cases where it would just plain fail (but then work if re-run).

We do use private scoped packages a lot so that might have some bearing on it.

I use private scoped packages (and monorepos, and yarn) too, and have generally had a fine time with it.

Would be interested in specifics of your reliability and failure problems too.

We just started using yarn workspaces and are running into weird issues where our private scoped packages don't always get installed on `yarn install`.

Yarn claims to be deterministic but I still need to `rm -rf node_modules` regularly when I run into weird build errors. It's quite strange.

Well... I don’t use it anymore because frankly, there’s no need.

Is there any chance that you are using npm to install yarn?

I had mistakenly setup our CI to do that at one point and it caused a lot of hard to debug problems.

I was not, but even if I was that speaks to Yarn’s quality imo because they recommend that as an option.

We finally got NPM out of the loop for production deploys and it's been glorious. We ship down a tarball of the repo after an npm install and include a node interpreter.

Ah well, that’s a whole different kind of system. Similar to doing a docker image ship.

Still have to do the install on a deploy server.

seems like a perfect use case for Docker.

I whole heartedly agree. Would you tell that to my boss? :D

Agreed. I tried to switch to yarn a couple times now and it simply wasn't reliable (though the last attempt was a few months ago)

Yea I'm big fan of it. Strange things used to happen with npm, dependencies would break, installs would fail etc... Maybe something to do with our build config, but since moving to yarn, no problems. We don't ever think about packages breaking or anything now (which is how it should be).