Exactly. PHP (like every other modern programming language) has its own dependency management tools. Node is actually better than many in this respect because npm comes bundled with Node — it's not something you have to install separately.

Ironically, Composer actually lists npm as one of its inspirations [1].

> "...Composer is strongly inspired by node's npm and ruby's bundler."

[1] https://getcomposer.org/doc/00-intro.md