Fast: Yarn caches every package it has downloaded, so it never needs to
download the same package again. It also does almost everything concurrently to
maximize resource utilization. This means even faster installs.

Reliable: Using a detailed but concise lockfile format and a deterministic
algorithm for install operations, Yarn is able to guarantee that any
installation that works on one system will work exactly the same on another
system.

Secure: Yarn uses checksums to verify the integrity of every installed package
before its code is executed.