Facebook released Yarn, a package manager to replace NPM.  Here’s a tldr of why it’s a big deal:

• Official URL: https://yarnpkg.com/
• Facebook, with large code base and thousands of engineers struggled with NPM
• Problems with consistency, security, and performance are hard to solve.
• Yarn was a result of their internal tweaks to NPM and collaboration effort from Exponent, Google, and Tilde.
• Yarn is NOT a package registry. Yarn pulls packages from registry.yarnpkg.com, which allows them to run experiments with the Yarn client. This is a proxy that pulls packages from the official npm registry, much like npmjs.cf.
• “With Yarn, engineers still have access to the npm registry, but can install packages more quickly and manage dependencies consistently across machines or in secure offline environments.”
• Problems with NPM: node_modules tree structure could be different depend on the order modules are installed, thus making it non-deterministic, Yarn solves that by using lockfiles and recursively install modules with a deterministic algorithm
• Package checksums are stored in lockfiles
• Global module cache to help reduce installation time
• Backwards compatible with NPM and Bower
• Start using it by: npm install -g yarn
• Instead of npm install you simply do yarn
• Instead of npm install something –save you do yarn add something
• This thing is SUPER FAST! https://yarnpkg.com/en/compare
• Does NOT work with installing private npm modules or Github at the moment but it may come soon, help contribute! https://github.com/yarnpkg/yarn/issues/521
• Why I’m Working on Yarn by one of the contributers, Yehuda Katz

NPM vs Yarn speed comparison