Feature/dev 1022 elementcollection w ids

[brandonkelly]

Description

Adds a new craft\elements\ElementCollection class, which extends Illuminate\Support\Collection specifically for collecting element instances, and adds two new methods:

• ids() – returns a new collection of the IDs of each of the collected elements. (#12113)
• with() - eager-loads additional elements onto the collected elements and then returns the same ElementCollection object.

craft\elements\db\ElementQuery::collect() and craft\base\Element::getEagerLoadedElements() have both been updated to return new ElementCollection instances rather than Collection, so the following are now possible:

{% set ids = craft.entries()
  .collect()
  .ids() %}

{% set entries = craft.entries()
  .collect()
  .with(['eagerLoadingHandle']) %}

{% for entry in entries %}
  {% set eagerLoadedIds = entry.eagerLoadingHandle.ids() %}
{% endfor %}

Related issues

• Add Collection `ids` macro #12113

[linear]

DEV-1022 ElementCollection w/ ids()