The one-size-fits-all polyfill for PHP.
Polyphill is a metapackage for PHP that installs the polyfills you need, and removes those that are redundant.
composer require 'empaphy/polyphill:^1'
Polyphill does some clever composer dependency tricks to ensure that polyfills are only installed if your composer dependencies contain an explicit requirement for a polyfillable extension not natively provided by your platform.
This keeps your vendor directory free from unused packages in the best-case scenario, while ensuring maximum compatability on environments that miss any required extensions.