Facebook hasn’t used PHP for a long time. They use Hack which started as a language similar to PHP, but it’s very different now - it’s strongly-typed and has a bunch of advanced features, like the ability to annotate functions as pure (no side effects), which gets enforced by the type checker.
Yeah…
Facebook hasn’t used PHP for a long time. They use Hack which started as a language similar to PHP, but it’s very different now - it’s strongly-typed and has a bunch of advanced features, like the ability to annotate functions as pure (no side effects), which gets enforced by the type checker.