feat: Add BindEl helper for DOM element wrapping

Author: mirkobrombin

v1/composition/node.go

@@ -27,6 +27,18 @@ func (e elWrap) Append(nodes ...Node) {
 	}
 }
 
+// BindEl invokes fn with a wrapper exposing Clear and Append helpers for the
+// provided element.
+func BindEl(el dom.Element, fn func(El)) {
+	if fn == nil {
+		panic("composition.BindEl: nil fn")
+	}
+	if el.IsNull() || el.IsUndefined() {
+		return
+	}
+	fn(elWrap{el})
+}
+
 // Bind selects the first element matching selector and invokes fn with a
 // wrapper exposing Clear and Append helpers.
 func Bind(selector string, fn func(El)) {
@@ -37,10 +49,7 @@ func Bind(selector string, fn func(El)) {
 		panic("composition.Bind: nil fn")
 	}
 	el := dom.Doc().Query(selector)
-	if el.IsNull() || el.IsUndefined() {
-		return
-	}
-	fn(elWrap{el})
+	BindEl(el, fn)
 }
 
 // For repeatedly calls fn to generate nodes and appends them to the element

v1/composition/node_test.go

@@ -23,6 +23,21 @@ func TestBind(t *testing.T) {
 	}
 }
 
+func TestBindEl(t *testing.T) {
+	doc := dom.Doc()
+	doc.Body().SetHTML("<div id='root'><span>old</span></div>")
+
+	BindEl(doc.ByID("root"), func(el El) {
+		el.Clear()
+		el.Append(Div().Text("new"))
+	})
+
+	root := doc.ByID("root")
+	if html := root.HTML(); html != "<div>new</div>" {
+		t.Fatalf("expected <div>new</div>, got %q", html)
+	}
+}
+
 func TestFor(t *testing.T) {
 	doc := dom.Doc()
 	doc.Body().SetHTML("<div id='list'></div>")