add Index() methods

array.go

@@ -41,3 +41,49 @@ func (this *Selection) Get(index int) *html.Node {
 	}
 	return this.Nodes[index]
 }
+
+// Index() returns the position of the first element within the Selection object relative to
+// its sibling elements.
+func (this *Selection) Index() int {
+	// TODO : Eventually refactor with prevAll(), like jQuery's code
+	if len(this.Nodes) > 0 {
+		n := this.Nodes[0]
+		if p := n.Parent; p != nil {
+			var i = 0
+			for _, c := range p.Child {
+				if c == n {
+					// This is the index of the element
+					return i
+				} else if c.Type == html.ElementNode {
+					i++
+				}
+			}
+		}
+	}
+	return -1
+}
+
+// IndexSelector() returns the position of the first element within the Selection object
+// relative to the elements matched by the selector, or -1 if not found.
+func (this *Selection) IndexSelector(selector string) int {
+	if len(this.Nodes) > 0 {
+		sel := this.document.Find(selector)
+		return indexInSlice(sel.Nodes, this.Nodes[0])
+	}
+	return -1
+}
+
+// IndexOfNode() returns the position of the specified node within the Selection object,
+// or -1 if not found.
+func (this *Selection) IndexOfNode(node *html.Node) int {
+	return indexInSlice(this.Nodes, node)
+}
+
+// IndexOfSelection() returns the position of the first node in the specified Selection object
+// within this Selection object, or -1 if not found.
+func (this *Selection) IndexOfSelection(s *Selection) int {
+	if len(s.Nodes) > 0 {
+		return indexInSlice(this.Nodes, s.Nodes[0])
+	}
+	return -1
+}

array_test.go

@@ -93,3 +93,39 @@ func TestGetInvalid(t *testing.T) {
 	sel := doc.Find(".pvk-content")
 	sel.Get(129)
 }
+
+func TestIndex(t *testing.T) {
+	sel := doc.Find(".pvk-content")
+	if i := sel.Index(); i != 1 {
+		t.Errorf("Expected index of 1, got %v.", i)
+	}
+}
+
+func TestIndexSelector(t *testing.T) {
+	sel := doc.Find(".hero-unit")
+	if i := sel.IndexSelector("div"); i != 4 {
+		t.Errorf("Expected index of 4, got %v.", i)
+	}
+}
+
+func TestIndexOfNode(t *testing.T) {
+	sel := doc.Find("div.pvk-gutter")
+	if i := sel.IndexOfNode(sel.Nodes[1]); i != 1 {
+		t.Errorf("Expected index of 1, got %v.", i)
+	}
+}
+
+func TestIndexOfNilNode(t *testing.T) {
+	sel := doc.Find("div.pvk-gutter")
+	if i := sel.IndexOfNode(nil); i != -1 {
+		t.Errorf("Expected index of -1, got %v.", i)
+	}
+}
+
+func TestIndexOfSelection(t *testing.T) {
+	sel := doc.Find("div")
+	sel2 := doc.Find(".hero-unit")
+	if i := sel.IndexOfSelection(sel2); i != 4 {
+		t.Errorf("Expected index of 4, got %v.", i)
+	}
+}

utilities.go

@@ -47,12 +47,19 @@ func nodeContains(container *html.Node, contained *html.Node) bool {
 
 // Checks if the target node is in the slice of nodes.
 func isInSlice(slice []*html.Node, node *html.Node) bool {
-	for _, n := range slice {
+	return indexInSlice(slice, node) > -1
+}
+
+// Returns the index of the target node in the slice, or -1.
+func indexInSlice(slice []*html.Node, node *html.Node) int {
+	if node != nil {
+		for i, n := range slice {
 			if n == node {
-			return true
+				return i
 			}
 		}
-	return false
+	}
+	return -1
 }
 
 // Appends the new nodes to the target slice, making sure no duplicate is added.