npm
npm is the Node Package Manager.
- It is an executable that comes with node for installing packages.
- As well as a registery and host for those packages.
- You can publish packages quite easily.
- It is also a bit slow sometimes.
There are various sites for searching and exploring what's out there:
yarn
yarn is a new alternative to npm from facebook.
It is much much faster, uses a local cache to avoid re-downloading and can even work offline. Since some packages may compile c++ for your system, it can save a significant amount of time to have a local cache.
yarn uses the same registery and supports the same cli features as npm. It is a drop-in replacement.
You might want to stick to npm until you feel confident with the eco-system. npm and yarn installed together can sometimes cause some head scratching.
It's quite easy to switch a project to yarn later - just delete your node_modules folder and run yarn install