wip: minimal component implementation

packages/runtime-core/src/component.ts

@@ -1 +1,46 @@
+import { VNode, normalizeVNode } from './vnode'
+
 export class Component {}
+
+export function renderComponentRoot(instance: any): VNode {
+  return normalizeVNode(instance.render(instance.vnode.props))
+}
+
+export function shouldUpdateComponent(
+  prevVNode: VNode,
+  nextVNode: VNode
+): boolean {
+  const { props: prevProps } = prevVNode
+  const { props: nextProps } = nextVNode
+
+  // TODO handle slots
+  // If has different slots content, or has non-compiled slots,
+  // the child needs to be force updated.
+  // if (
+  //   prevChildFlags !== nextChildFlags ||
+  //   (nextChildFlags & ChildrenFlags.DYNAMIC_SLOTS) > 0
+  // ) {
+  //   return true
+  // }
+
+  if (prevProps === nextProps) {
+    return false
+  }
+  if (prevProps === null) {
+    return nextProps !== null
+  }
+  if (nextProps === null) {
+    return prevProps !== null
+  }
+  const nextKeys = Object.keys(nextProps)
+  if (nextKeys.length !== Object.keys(prevProps).length) {
+    return true
+  }
+  for (let i = 0; i < nextKeys.length; i++) {
+    const key = nextKeys[i]
+    if (nextProps[key] !== prevProps[key]) {
+      return true
+    }
+  }
+  return false
+}