Npm has version locks via npm-shrinkwrap.json. We will be happy if Yarn inspires npm CLI, some competition is always good

yarn.lock is your source of truth, better keep it in version control to get reproducible builds. We decided not to follow shrinkwrap json format because it is hard to read and review. There are a few differences how it stores deep trees and that yarn.lock entries are sorted thus making git conflicts less common

Everyone should use Yarn

I am planning to release a blog post at https://yarnpkg.com/blog/ about the offline mode. Next week hopefully.

Afaik there is no native support for emojis in Windows terminal

Yarn follows the same model as npm@3. It tries to flatten packages if there are no conflicts, in that case it makes them nested. There is an option to force flat node_modules in Yarn, then you would have to resolve package conflicts manually.

We saw a problem - we solved it, we iterate on improving it. Same thing about all the other libraries/projects/platforms in the JS ecosystem.

Isn't everything in JS community a temporary solution to a problem? Adopting Yarn is not that hard, it is still compatible with commonjs/node modules resolution

we try to cut branch every two weeks but a more governed way to make releases is in discussion

All the people in my team have an apple logo on their computers. FB engineers have some flexibility to what tools and devices they need to perform.