Composer is dependency management for PHP, and it consists of two main files:
composer.jsonwhere you specify your dependenciescomposer.lockwhere composer itself records exactly which precise version of every library and every dependency of every library it picked, so all installs will be identical
Crucially, the composer.lock also includes a hash of the current composer.json when it updates, so you can always tell if you’ve added a requirement to the composer.json file and forgotten to install it. Continue reading
