Add key field to UElement (ADR-004)

src/core/h.ts

@@ -3,7 +3,8 @@ import type { UNode, UElement, URoot, UType, UComponent, UniversalProps } from "
 let _idCounter = 0;
 
 export function h(type: UType, props?: UniversalProps | null, ...children: UNode[]): UElement | URoot {
-  const resolvedProps: UniversalProps = props ? { ...props } : {};
+  const { key, ...restProps } = props ?? {};
+  const resolvedProps: UniversalProps = restProps;
   const flatChildren = children.flat(Infinity as 1).filter((c: UNode) => c != null && c !== false) as UNode[];
 
   if (type === "root") {
@@ -18,6 +19,7 @@ export function h(type: UType, props?: UniversalProps | null, ...children: UNode
     type: type as string,
     props: resolvedProps,
     children: flatChildren,
+    ...(key != null ? { key: key as string } : {}),
   } as UElement;
 }
 

src/core/schema.ts

@@ -23,6 +23,7 @@ export const UJSX = Type.Module({
     type: Type.String(),
     props: Type.Ref("UniversalProps"),
     children: Type.Array(Type.Ref("UNode")),
+    key: Type.Optional(Type.String()),
   }),
 
   URoot: Type.Object({
@@ -45,6 +46,7 @@ export type UElement = {
   type: string;
   props: UniversalProps;
   children: UNode[];
+  key?: string;
 };
 export type URoot = {
   type: "root";