manipulation: Add Before*() functions.

manipulation.go

@@ -164,6 +164,43 @@ func (s *Selection) AppendNodes(ns ...*html.Node) *Selection {
 	})
 }
 
+// From the root document, apply the selector, and insert the matched elements
+// before each element in the set of matched elements.
+// This follows the same rules as Selection.After().
+func (s *Selection) Before(selector string) *Selection {
+	return s.BeforeSelector(cascadia.MustCompile(selector))
+}
+
+// From the root document, apply the cascadia selector, and insert the matched
+// elements before each element in the set of matched elements.
+// This follows the same rules as Selection.After().
+func (s *Selection) BeforeSelector(cs cascadia.Selector) *Selection {
+	return s.BeforeNodes(cs.MatchAll(s.document.rootNode)...)
+}
+
+// Insert the elements in the selection before each element in the set of matched
+// elements.
+// This follows the same rules as Selection.After().
+func (s *Selection) BeforeSelection(sel *Selection) *Selection {
+	return s.BeforeNodes(sel.Nodes...)
+}
+
+// Parse the html and insert it before the set of matched elements
+// This follows the same rules as Selection.After().
+func (s *Selection) BeforeHtml(html string) *Selection {
+	return s.BeforeSelection(parseHtml(html))
+}
+
+// Insert the nodes before each element in the set of matched elements.
+// This follows the same rules as Selection.After().
+func (s *Selection) BeforeNodes(ns ...*html.Node) *Selection {
+	return s.manipulateNodes(ns, false, func(sn *html.Node, n *html.Node) {
+		if sn.Parent != nil {
+			sn.Parent.InsertBefore(n, sn)
+		}
+	})
+}
+
 // Create a deep copy of the set of matched nodes. The new nodes will not be
 // attached to the document.
 func (s *Selection) Clone() *Selection {

manipulation_test.go

@@ -79,6 +79,41 @@ func TestAppendHtml(t *testing.T) {
 
 	AssertLength(t, doc.Find("strong").Nodes, 14)
 }
+
+func TestBefore(t *testing.T) {
+	doc := Doc2Clone()
+	doc.Find("#main").Before("#nf6")
+
+	AssertLength(t, doc.Find("#main #nf6").Nodes, 0)
+	AssertLength(t, doc.Find("#foot #nf6").Nodes, 0)
+	AssertLength(t, doc.Find("body > #nf6:first-child").Nodes, 1)
+}
+
+func TestBeforeWithRemoved(t *testing.T) {
+	doc := Doc2Clone()
+	s := doc.Find("#main").Remove()
+	s.Before("#nf6")
+
+	AssertLength(t, s.Find("#nf6").Nodes, 0)
+	AssertLength(t, doc.Find("#nf6").Nodes, 0)
+}
+
+func TestBeforeSelection(t *testing.T) {
+	doc := Doc2Clone()
+	doc.Find("#main").BeforeSelection(doc.Find("#nf1, #nf2"))
+
+	AssertLength(t, doc.Find("#main #nf1, #main #nf2").Nodes, 0)
+	AssertLength(t, doc.Find("#foot #nf1, #foot #nf2").Nodes, 0)
+	AssertLength(t, doc.Find("body > #nf1:first-child, #nf1 + #nf2").Nodes, 2)
+}
+
+func TestBeforeHtml(t *testing.T) {
+	doc := Doc2Clone()
+	doc.Find("#main").BeforeHtml("<strong>new node</strong>")
+
+	AssertLength(t, doc.Find("body > strong:first-child").Nodes, 1)
+}
+
 func TestEmpty(t *testing.T) {
 	doc := Doc2Clone()
 	s := doc.Find("#main").Empty()