wasm tools

wasm/wasm.go

@@ -0,0 +1,104 @@
+package wasm
+
+import (
+	"strconv"
+	"syscall/js"
+)
+
+type Node struct {
+	tag       string
+	id        string
+	attrs     []*Attribute
+	children  []*Node
+	jsElement js.Value
+	innerText string
+}
+
+type Attribute struct {
+	Name  string
+	Value string
+}
+
+func document(document js.Value) *Node {
+	return &Node{jsElement: document}
+}
+
+func (n *Node) createElement(document js.Value) {
+	var el = document.Call("createElement", n.tag)
+	el.Call("setAttribute", "id", n.id)
+	for _, attr := range n.attrs {
+		el.Call("setAttribute", attr.Name, attr.Value)
+	}
+	n.jsElement = el
+}
+
+func (n *Node) AppendChild(child *Node) {
+	if child.tag != "" {
+		n.children = append(n.children, child)
+		n.jsElement.Call("appendChild", child.jsElement)
+	} else {
+		n.jsElement.Set("innerText", child.innerText)
+	}
+}
+
+func (n *Node) GetChildren() []*Node {
+	return n.children
+}
+
+func (n *Node) ReplaceChildren(newChildren []*Node) {
+	n.children = newChildren
+	for {
+		child := n.jsElement.Get("firstChild")
+		if child.IsNull() {
+			break
+		}
+		n.jsElement.Call("removeChild", child)
+	}
+	for _, child := range n.children {
+		n.AppendChild(child)
+	}
+}
+
+type NodeFactory struct {
+	document  *Node
+	idCounter int64
+	root      *Node
+}
+
+func NewNodeFactory(jsDocument js.Value) *NodeFactory {
+	var f = &NodeFactory{document: document(jsDocument), idCounter: 0}
+	f.setRoot()
+	return f
+}
+
+func (f *NodeFactory) setRoot() {
+	var rootElement = f.document.jsElement.Get("firstElementChild")
+	if rootElement.IsNull() {
+		f.root = f.NewNode("html")
+	} else {
+		f.root = &Node{tag: "html", jsElement: rootElement}
+		f.document.AppendChild(f.root)
+	}
+}
+
+func (f *NodeFactory) Root() *Node {
+	return f.root
+}
+
+func (f *NodeFactory) NewBody() *Node {
+	var body = f.NewNode("body")
+	f.root.AppendChild(body)
+	return body
+}
+
+func (f *NodeFactory) NewNode(tag string, attributes ...*Attribute) *Node {
+	var id = f.idCounter
+	f.idCounter++
+	var n = &Node{tag: tag, id: strconv.FormatInt(id, 10), attrs: attributes}
+	n.createElement(f.document.jsElement)
+	return n
+}
+
+func (f *NodeFactory) NewTextNode(text string) *Node {
+	return &Node{innerText: text}
+}