Add unusedtitle macro (#3880)

* Add uniquetitle macro

This macro is a wrapper on the $tw.wiki.generateNewTitle function to return a unique name, it has been requested multiple times in the forums.

* Add documentation tiddler for uniquetitle macro

* Add uniquetitle macro examples

* Change name from uniquetitle to unusedtitle for clarity

The title isn't unique, just not currently used in the wiki.

* Update uniquetitle to unusedtitle

* Change uniquetitle to unusedtitle

* Fix a typo

core/modules/macros/uniquetitle.js

@@ -0,0 +1,34 @@
+/*\
+title: $:/core/modules/macros/unusedtitle.js
+type: application/javascript
+module-type: macro
+Macro to return a new title that is unused in the wiki. It can be given a name as a base.
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+/*
+Information about this macro
+*/
+
+exports.name = "unusedtitle";
+
+exports.params = [
+	{name: "baseName"},
+	{name: "options"}
+];
+
+/*
+Run the macro
+*/
+exports.run = function(baseName, options) {
+	if(!baseName) {
+		baseName = $tw.language.getString("DefaultNewTiddlerTitle");
+	}
+	return this.wiki.generateNewTitle(baseName, options);
+};
+
+})();

editions/tw5.com/tiddlers/macros/UnusedTitleMacro.tid

@@ -0,0 +1,16 @@
+
+caption: unusedtitle
+tags: Macros [[Core Macros]]
+title: unusedtitle Macro
+type: text/vnd.tiddlywiki
+
+The <<.def unusedtitle>> [[macro|Macros]] returns an unused title. Optionally you can provide a base title to generate the new title.
+
+It uses the same method as the create new tiddler button, a number is appended to the end of the base name.
+
+!! Parameters
+
+;baseName
+: A string specifying the desired base name, defaulting to `New Tiddler`
+
+<<.macro-examples "unusedtitle">>

editions/tw5.com/tiddlers/macros/examples/unusedtitle.tid

@@ -0,0 +1,7 @@
+tags: [[unusedtitle Macro]] [[Macro Examples]]
+title: unusedtitle Macro (Examples)
+type: text/vnd.tiddlywiki
+
+<$macrocall $name=".example" n="1" eg="""<<unusedtitle>>"""/>
+<$macrocall $name=".example" n="2" eg="""<<unusedtitle AnotherBase>>"""/>
+<$macrocall $name=".example" n="3" eg="""<<unusedtitle TiddlyWiki>>"""/>