As powerful as npm is, it is not the only package management system for Node.js. Because the Node.js core team does not dictate a package management system, the Node.js community is free to roll up their sleeves and develop any system they feel best. That the vast majority of us use npm is a testament to its value and usefulness. But, there is a significant competitor.
Yarn (see https://yarnpkg.com/en/) is a collaboration between engineers at Facebook, Google, and several other companies. They proclaim that Yarn is ultrafast, ultra-secure (by using checksums of everything), and ultrareliable (by using a yarn-lock.json file to record precise dependencies).
Instead of running their own package repository, Yarn runs on top of the npm package repository at npmjs.com. This means that the Node.js community is not forked by Yarn, but enhanced by having an improved package management tool.
The npm team responded to Yarn in npm@5 (also known as npm version 5...
