Use constants as array keys

When strings are used as array keys there is no difference between the key used to define the identifier of a route and that of a record. It may become quite troublesome when you need to search for common keys such as id, name, or title; for instance when you need to rename records 'id' as 'article_id'. Also, using strings as array keys may introduce errors such as misspelling and use of deprecated/extraneous keys.

The following code is an example of strings used as array keys:

<?php

$route = [ 'id' => 'articles:edit', … ];
$record = Record::from([ 'id' => 123 ]);

For all these reasons I recommend the use of constants such as ROUTE_ID and ARTICLE_ID. Your lovely IDE will help you avoid misspells, and will even warn you when a constant is marked as deprecated. But instead of defining constants in some namespace, I prefer to define them in classes or interfaces with a clear purpose. For instance, I'd use constants such as RouteDefinition::ID and Article::ID.

Consider the following route definition, using strings to define keys and some special values.

<?php

$definition = [

    'pattern' => '/articles/<id:\d+>/edit',
    'controller' => ArticleController::class,
    'action' => 'edit',
    'via' => 'GET',
    'id' => 'articles:edit'

];

And now consider the following route definition, using constants:

<?php

use ICanBoogie\HTTP\Request;
use ICanBoogie\RouteDefinition;

$definition = [

    RouteDefinition::PATTERN => '/articles/<id:\d+>/edit',
    RouteDefinition::CONTROLLER => ArticleController::class,
    RouteDefinition::ACTION => RouteDefinition::ACTION_EDIT,
    RouteDefinition::VIA => Request::METHOD_GET,
    RouteDefinition::ID => 'articles:edit'

];

That's a little more work, but I'm confident that these keys exists and now it would be child's play to search for route definition identifiers.

tl;dr

Define constants to use as array keys, and group them in classes/interfaces relevant to their purpose.