Add the count widget

core/modules/new_widgets/count.js

@@ -0,0 +1,81 @@
+/*\
+title: $:/core/modules/new_widgets/count.js
+type: application/javascript
+module-type: new_widget
+
+Count widget
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+var Widget = require("$:/core/modules/new_widgets/widget.js").widget;
+
+var CountWidget = function(parseTreeNode,options) {
+	this.initialise(parseTreeNode,options);
+};
+
+/*
+Inherit from the base widget class
+*/
+CountWidget.prototype = new Widget();
+
+/*
+Render this widget into the DOM
+*/
+CountWidget.prototype.render = function(parent,nextSibling) {
+	this.parentDomNode = parent;
+	this.computeAttributes();
+	this.execute();
+	var textNode = this.document.createTextNode(this.currentCount);
+	parent.insertBefore(textNode,nextSibling);
+	this.domNodes.push(textNode);
+};
+
+/*
+Compute the internal state of the widget
+*/
+CountWidget.prototype.execute = function() {
+	// Get parameters from our attributes
+	this.filter = this.getAttribute("filter");
+	// Execute the filter
+	if(this.filter) {
+		this.currentCount = this.wiki.filterTiddlers(this.filter,this.getVariable("tiddlerTitle")).length;
+	} else {
+		this.currentCount = undefined;
+	}
+};
+
+/*
+Selectively refreshes the widget if needed. Returns true if the widget or any of its children needed re-rendering
+*/
+CountWidget.prototype.refresh = function(changedTiddlers) {
+	// Re-execute the filter to get the count
+	var oldCount = this.currentCount;
+	this.execute();
+	if(this.currentCount !== oldCount) {
+		// Regenerate and rerender the widget and replace the existing DOM node
+		this.refreshSelf();
+		return true;
+	} else {
+		return false;
+	}
+
+};
+
+/*
+Remove any DOM nodes created by this widget
+*/
+CountWidget.prototype.removeChildDomNodes = function() {
+	$tw.utils.each(this.domNodes,function(domNode) {
+		domNode.parentNode.removeChild(domNode);
+	});
+	this.domNodes = [];
+};
+
+exports.count = CountWidget;
+
+})();