Testing dom diffing

src/main/kotlin/nl/astraeus/komp/DomDiff.kt

@@ -0,0 +1,65 @@
+package nl.astraeus.komp
+
+import org.w3c.dom.HTMLElement
+import org.w3c.dom.get
+
+/**
+ * User: rnentjes
+ * Date: 10-9-17
+ * Time: 13:33
+ */
+
+object DomDiffer {
+
+    fun replaceDiff(newElement: HTMLElement, oldElement: HTMLElement) {
+        if (!match(newElement, oldElement)) {
+            replaceNode(newElement, oldElement)
+        } else {
+            // think of the children!
+            for (index in 0 until newElement.childElementCount) {
+                val newChild = newElement.children[index]
+                val oldChild = oldElement.children[index]
+
+                if (newChild is HTMLElement && oldChild is HTMLElement) {
+                    replaceDiff(newChild, oldChild)
+                }
+            }
+        }
+    }
+
+    private fun replaceNode(newElement: HTMLElement, oldElement: HTMLElement) {
+        val parent = oldElement.parentElement
+
+        parent?.replaceChild(newElement, oldElement)
+    }
+
+    fun match(newElement: HTMLElement, oldElement: HTMLElement): Boolean {
+        var result = true
+
+        result = result && newElement.namespaceURI == oldElement.namespaceURI
+        result = result && newElement.nodeName == oldElement.nodeName
+        result = result && newElement.childElementCount == oldElement.childElementCount
+
+        val newAttr = newElement.attributes
+        val oldAttr = oldElement.attributes
+
+        result = result && newAttr.length == oldAttr.length
+
+        if (result) {
+            for (index in 0 until newAttr.length) {
+                val attr = newAttr[index]
+
+                if (attr != null) {
+                    result = result && newAttr.getNamedItem(attr.name)?.name == oldAttr.getNamedItem(attr.name)?.name
+                    result = result && newAttr.getNamedItem(attr.name)?.value == oldAttr.getNamedItem(attr.name)?.value
+                }
+                if (!result) {
+                    break
+                }
+            }
+        }
+
+        return result
+    }
+
+}