Facebook today launched Yarn,a collaboration with Exponent, Google, and Tilde.
Yarn is compatible with the npm registry, but differs in its approach to installing packages; it uses lockfiles and a deterministic installation algorithm.
This allows it to maintain the same structure of node_modules directories – which house dependencies – for all users involved in a project, and help reduce bugs that are difficult to trace and replicate on multiple machines.
Yarn also aims to ensure quicker and more reliable installs by caching every package it downloads and by parallelizing operations. It also allows for installing packages without an internet connection, provided you’ve installed them at least once before.
In addition, Yarn promises compatibility with both npm and Bower workflows, and lets you restrict licenses of installed modules.