How does PSR-4 autoloading work in composer for custom libraries?

Question

I use the following directory structure based on my understanding of how namespaces in PHP work:

project_root
    app/
    |    lib/
    |    |    MyCompany/         


        

Answer 1

Taken from the documentation you linked:

{
    "autoload": {
        "psr-4": {
            "MyCompany\\": "app/lib/MyCompany/",
        }
    }
}

This is pretty self explanatory, it simply tells the autoloader that app/lib/MyCompany is the root for the MyCompany\ namespace.

You would then be able to use the class as \MyCompany\Utility\Logger.

Note that in PSR-4, unlike PSR-0, you'd normally omit MyCompany from the directory structure, and just use app/lib/.