Unfortunately npm is probably the biggest source of my daily development frustrations, even on the latest version.
I still come across bugs (that are definitely in npm itself) that have been around absolutely forever, like:
> npm ERR! cb() never called!
It sometimes gets its primary purpose, dependency resolution, wrong. I'll give it a perfectly reasonable package.json to install, which it will do, and then `npm ls` will still error with "missing dependency!" in some package. This should not be possible.
Related, it will put packages from the flattened tree in the wrong place. I can have a dependency (that other dependencies need, specified in their peerDependencies) specified in my top-level package.json and bafflingly, npm will still move it from top-level node_modules into the node_modules of something else that happens to use it, breaking the peerDependencies I was trying to satisfy.
On the install process: even if the total time to install is roughly on par with Yarn, I find that Yarn is much smoother. Whatever they're doing, they're yielding the CPU a lot more, and the result is I can actually work while it installs. npm meanwhile doesn't yield much during install and slows the whole system to a crawl.
Some npm commands are extremely neglected. The "success" message printed by one of the user/permissions related commands is simply: {}
Kind of ridiculous, but yarn's CLI just feels better. It's a bit simpler, `install` doesn't really seem like an "add to package manifest" command word, there's the `global` subcommand for managing global command-line tools vs `-g`/`--global`, and no command aliases, which I like more for some reason. For me it's mostly personal preference; ergonomics would be the key difference for me. Plus, the upcoming stuff mentioned in this issue has got me excited!
Edit: also, in my experience using npm for some little stuff recently, yarn is still faster installing packages.
Edit2: I also like the ability to run scripts/commands from the base level of command, e.g. `yarn start`, `yarn webpack --mode production`, `yarn build:web`
