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In this section we are going to focus on the concept of sharing code

between multiple developers.

There are concepts such as auto loading, name spaces, and

file structures that help make all of this possible.

Then there are tools such as Composer which handle dependency management.

Depending on code from other developers means you need a way to

handle those dependencies.

Which is a bit more robust than downloading zip files and

copying things around.

Composer lets you do this.

So why would you want to use somebody else's code?

If you're doing something very common but

quite complex, like interacting with a popular API, integrating with oAuth, or

doing image manipulation, then you might benefit from using an existing package.

Popular code packages exist for a lot of these problems, and

they have been battle tested by hundreds or thousands of other users.

They might have features that you haven't considered yet, or

cater to edge cases that you have not yet discovered.

And generally, they'll help you get your job done much more quickly.

Thanks to Composer and

Packagist, PHP has more high quality packages than it's ever had before.

The majority of them use name spaces and

auto loading to make interacting with them incredibly easy.

Let's look how you can use Composer to install code from third party

developers so you can spend more time working on something awesome.