Feat/view button condition (#9466)

* feat: support condition field on $:/tags/ViewToolbar button

* Delete convert-markdown.tid

* Create #9466.tid

* Update title.tid

core/ui/ViewTemplate/title.tid

@@ -11,9 +11,13 @@ tags: $:/tags/ViewTemplate
 				storyview="pop"
 				variable="listItem"
 			>
-				<$set name="tv-config-toolbar-class" filter="[<tv-config-toolbar-class>] [<listItem>encodeuricomponent[]addprefix[tc-btn-]]">
-					<$transclude tiddler=<<listItem>>/>
-				</$set>
+				<$let condition={{{ [<listItem>get[condition]] }}}>
+					<%if [<condition>!is[blank]] :and[<currentTiddler>subfilter<condition>limit[1]] :else[<condition>is[blank]then[true]] %>
+						<$set name="tv-config-toolbar-class" filter="[<tv-config-toolbar-class>] [<listItem>encodeuricomponent[]addprefix[tc-btn-]]">
+							<$transclude tiddler=<<listItem>>/>
+						</$set>
+					<%endif%>
+				</$let>
 			</$list>
 		</span>
 		<$set name="tv-wikilinks" value={{$:/config/Tiddlers/TitleLinks}}>

editions/tw5.com/tiddlers/releasenotes/5.4.0/#9466.tid

@@ -0,0 +1,15 @@
+title: $:/changenotes/5.4.0/#9466
+description: ViewToolbar buttons now support condition field
+tags: $:/tags/ChangeNote
+release: 5.4.0
+change-type: feature
+change-category: hackability
+github-links: https://github.com/TiddlyWiki/TiddlyWiki5/pull/9466
+github-contributors: linonetwo
+
+ViewToolbar buttons can now be conditionally displayed based on the currentTiddler using a `condition` field. Similar to how `$:/tags/Exporter` and `$:/tags/EditorTools` already have. An example would be:
+
+```tid
+tags: $:/tags/ViewToolbar
+condition: [<currentTiddler>type[text/x-markdown]] [<currentTiddler>type[text/markdown]]
+```