Added a basic DOM diff algorithm

scripts/Diff.ts

@@ -1,5 +1,63 @@
 export class Diff {
-	static update(element: HTMLElement, html: string) {
-		element.innerHTML = html
+	static childNodes(aRoot: HTMLElement, bRoot: HTMLElement) {
+		let aChild = [...aRoot.childNodes]
+		let bChild = [...bRoot.childNodes]
+		let numNodes = Math.max(aChild.length, bChild.length)
+		
+		for(let i = 0; i < numNodes; i++) {
+			let a = aChild[i] as HTMLElement
+
+			if(i >= bChild.length) {
+				aRoot.removeChild(a)
+				continue
+			}
+
+			let b = bChild[i] as HTMLElement
+
+			if(i >= aChild.length) {
+				aRoot.appendChild(b)
+				continue
+			}
+
+			if(a.nodeName !== b.nodeName || a.nodeType !== b.nodeType) {
+				aRoot.replaceChild(b, a)
+				continue
+			}
+
+			if(a.nodeType === Node.ELEMENT_NODE) {
+				let removeAttributes: Attr[] = []
+				
+				for(let x = 0; x < a.attributes.length; x++) {
+					let attrib = a.attributes[x]
+
+					if(attrib.specified) {
+						if(!b.hasAttribute(attrib.name)) {
+							removeAttributes.push(attrib)
+						}
+					}
+				}
+
+				for(let attr of removeAttributes) {
+					a.removeAttributeNode(attr)
+				}
+
+				for(let x = 0; x < b.attributes.length; x++) {
+					let attrib = b.attributes[x]
+
+					if(attrib.specified) {
+						a.setAttribute(attrib.name, b.getAttribute(attrib.name))
+					}
+				}
+			}
+
+			Diff.childNodes(a, b)
+		}
+	}
+
+	static innerHTML(aRoot: HTMLElement, html: string) {
+		let bRoot = document.createElement("main")
+		bRoot.innerHTML = html
+
+		Diff.childNodes(aRoot, bRoot)
 	}
 }