From 125bfdfec63c3be1b7d94be2d03e21226fcf23f5 Mon Sep 17 00:00:00 2001
From: Derk-Jan Hartman <hartman.wiki@gmail.com>
Date: Sun, 21 Jun 2015 18:59:20 +0200
Subject: [PATCH 1/1] Add wikipage.categories hook

This will be especially useful for HotCat.

Bug: T53583
Change-Id: Id944029df180c80502840c118a58013ebb717e1f
---
 includes/skins/Skin.php                       |  2 +-
 .../mediawiki.action.edit.preview.js          |  4 +++-
 resources/src/mediawiki/page/ready.js         | 19 +++++++++++++++++++
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/includes/skins/Skin.php b/includes/skins/Skin.php
index dbb7c7ff02..83f119dabe 100644
--- a/includes/skins/Skin.php
+++ b/includes/skins/Skin.php
@@ -560,7 +560,7 @@ abstract class Skin extends ContextSource {
 			$classes .= ' catlinks-allhidden';
 		}
 
-		return "<div id='catlinks' class='$classes'>{$catlinks}</div>";
+		return "<div id='catlinks' class='$classes' data-mw='interface'>{$catlinks}</div>";
 	}
 
 	/**
diff --git a/resources/src/mediawiki.action/mediawiki.action.edit.preview.js b/resources/src/mediawiki.action/mediawiki.action.edit.preview.js
index 013d34fe7d..1d4d0e954c 100644
--- a/resources/src/mediawiki.action/mediawiki.action.edit.preview.js
+++ b/resources/src/mediawiki.action/mediawiki.action.edit.preview.js
@@ -174,7 +174,9 @@
 					);
 				}
 				if ( response.parse.categorieshtml ) {
-					$( '#catlinks' ).replaceWith( response.parse.categorieshtml[ '*' ] );
+					$content = $( $.parseHTML( response.parse.categorieshtml[ '*' ] ) );
+					mw.hook( 'wikipage.categories' ).fire( $content );
+					$( '.catlinks[data-mw="interface"]' ).replaceWith( $content );
 				}
 				if ( response.parse.templates ) {
 					newList = [];
diff --git a/resources/src/mediawiki/page/ready.js b/resources/src/mediawiki/page/ready.js
index 9505bdd1e0..4385a2e903 100644
--- a/resources/src/mediawiki/page/ready.js
+++ b/resources/src/mediawiki/page/ready.js
@@ -70,6 +70,25 @@
 			} );
 		}
 
+		$nodes = $( '.catlinks[data-mw="interface"]' );
+		if ( $nodes.length ) {
+			/**
+			 * Fired when categories are being added to the DOM
+			 *
+			 * It is encouraged to fire it before the main DOM is changed (when $content
+			 * is still detached).  However, this order is not defined either way, so you
+			 * should only rely on $content itself.
+			 *
+			 * This includes the ready event on a page load (including post-edit loads)
+			 * and when content has been previewed with LivePreview.
+			 *
+			 * @event wikipage_categories
+			 * @member mw.hook
+			 * @param {jQuery} $content The most appropriate element containing the content,
+			 *   such as .catlinks
+			 */
+			mw.hook( 'wikipage.categories' ).fire( $nodes );
+		}
 	} );
 
 }( mediaWiki, jQuery ) );
-- 
2.20.1