Implement #getItems(match) on Project and Item as a simple and efficient query interface.

src/item/Item.js

@@ -1234,6 +1234,56 @@ var Item = Base.extend(Callback, /** @lends Item# */{
 		return this._parent ? this._parent.isInserted() : false;
 	},
 
+	// DOCS: Item#getItems
+	getItems: function(match) {
+		var children = this.children,
+			items = [];
+		for (var i = 0, l = children && children.length; i < l; i++) {
+			var child = children[i];
+			if (child.matches(match))
+				items.push(child);
+			items.push.apply(items, child.getItems(match));
+		}
+		return items;
+	},
+
+	// DOCS: Item#matches
+	matches: function(match) {
+		// matchObject() is used to match against objects in a nested manner.
+		// This is useful for matching against Item#data.
+		function matchObject(obj1, obj2) {
+			for (var i in obj1) {
+				if (obj1.hasOwnProperty(i)) {
+					var val1 = obj1[i],
+						val2 = obj2[i];
+					if (Base.isPlainObject(val1) && Base.isPlainObject(val2)) {
+						if (!matchObject(val1, val2))
+							return false;
+					} else if (!Base.equals(val1, val2)) {
+						return false;
+					}
+				}
+			}
+			return true;
+		}
+		for (var key in match) {
+			if (match.hasOwnProperty(key)) {
+				var value = this[key],
+					compare = match[key];
+				if (compare instanceof RegExp) {
+					if (!compare.test(value))
+						return false;
+				} else if (Base.isPlainObject(compare)) {
+					if (!matchObject(compare, value))
+						return false;
+				} else if (!Base.equals(value, compare)) {
+					return false;
+				}
+			}
+		}
+		return true;
+	},
+
 	equals: function(item) {
 		// Note: We do not compare name and selected state.
 		return item === this || item && this._class === item._class

src/project/Project.js

@@ -154,6 +154,15 @@ var Project = PaperScopeItem.extend(/** @lends Project# */{
 		return this._index;
 	},
 
+	// DOCS: Project#getItems
+	getItems: function(match) {
+		var layers = this.layers,
+			items = [];
+		for (var i = 0, l = layers.length; i < l; i++)
+			items.push.apply(items, layers[i].getItems(match));
+		return items;
+	},
+
 	/**
 	 * The selected items contained within the project.
 	 *
@@ -202,16 +211,18 @@ var Project = PaperScopeItem.extend(/** @lends Project# */{
 	 * Selects all items in the project.
 	 */
 	selectAll: function() {
-		for (var i = 0, l = this.layers.length; i < l; i++)
-			this.layers[i].setFullySelected(true);
+		var layers = this.layers;
+		for (var i = 0, l = layers.length; i < l; i++)
+			layers[i].setFullySelected(true);
 	},
 
 	/**
 	 * Deselects all selected items in the project.
 	 */
 	deselectAll: function() {
-		for (var i in this._selectedItems)
-			this._selectedItems[i].setFullySelected(false);
+		var selectedItems = this._selectedItems;
+		for (var i in selectedItems)
+			selectedItems[i].setFullySelected(false);
 	},
 
 	/**