We use Yarn because it allows us to more simply manage our node_modules. It also simplifies commands and increases speed when installing modules. Our teams module download time was cut in half after switching from NPM to Yarn. We now require all employees to use Yarn (to prevent errors with package-lock.json and yarn.lock).

I use npm since new version is pretty fast as well (Yarn may be still faster a bit but the difference isn't huge). No need for other dependency and mainly Yarn sometimes do not work. Sometimes when I want to install project dependencies I got error using Yarn but with npm everything is installed correctly.

p.s.

I am not sure about the performance of the latest version of npm, whether it is different from my understanding of it below. Because I use npm very rarely when I had the following knowledge.

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I use Yarn because, first, yarn is the first tool to lock the version. Second, although npm also supports the lock version, when you use npm to lock the version, and then use package-lock.json on other systems, package-lock.json Will be modified. You understand what I mean, when you deploy projects based on Git...

I use npm because I also mainly use React and TypeScript. Since several typings (from DefinitelyTyped) depend on the React typings, Yarn tends to mess up which leads to duplicate libraries present (different versions of the same type definition), which hinders the Typescript compiler. Npm always resolves to a single version per transitive dependency. At least that's my experience with both.

As far as I know Yarn is a super module of NPM. But it still needs npm to run.

Yarn was developed by Facebook's guys to fix some npm issues and performance.

If you use the last version of npm most of this problem does not exist anymore.

You can choose the option which makes you more confortable. I like using yarn because I'm used to it.

In the end the packages will be the same. Just try both and choose the one you feel more confortable. :)

Yarn made it painless for the team to sync on versions of packages that we use on the project <3

I use Yarn because it outputs nice progress messages with cute emoji and installs packages quickly if the package is cached. Also, Yarn creates yarn.lock file which makes the developer use the consistent environment.

I use npm because its the official package manager for Node. It's reliability, security and speed has increased over time so the battle is over!

I use npm because it has a lot of community support and the performance difference with alternative tool is not so significant for me.

You should use whichever had the best DX (developer experience) for your team. If you are doing a massive front-end project, consider yarn if not only because it makes it a snap to go from zero to ready. What some people say about npm being more stable or easier for smaller projects is highly true as well. (not to mention, you sometimes have to install yarn) But, note that official NodeJS Docker images ship with both npm and yarn. If you want to use yarn, put package-lock=false and optionally save-exact=true in your project's .npmrc file. Compare whether you prefer the ergonomics of yarn global add over npm install -g or see fewer meaningless warnings for the specific set of dependencies you leverage.

I use Yarn because it process my dependencies way faster, predictable deps resolution order, upgrade-interactive is very handy + some Yarn specific features (workspaces, Plug’n’Play alternative installation strategy) ...

We tend to stick to npm, yarn is only a fancy alternative, not 10x better. Using a self -hosted private repository (via sinopia/npm-mirror) make package locking (mostly) pointless.

I am a minimalist too. I once had issues with installing Nuxt.js using NPM so I had to install Yarn but I also found that the Dev experience was much better

I use npm because its packaged with node installation and handles npm tokens in CI/CD tools for private packages/libraries.