initial migration to TS

frontend/src/groupSizing.ts

@@ -0,0 +1,43 @@
+const DEFAULT_CHILD_WIDTH = 200;
+const DEFAULT_CHILD_HEIGHT = 120;
+
+interface SizableNode {
+  position?: { x: number; y: number };
+  measured?: { width?: number; height?: number };
+  width?: number;
+  height?: number;
+  style?: Record<string, unknown>;
+}
+
+function getNodeSize(node: SizableNode | null | undefined, axis: 'width' | 'height'): number {
+  const fallback = axis === 'width' ? DEFAULT_CHILD_WIDTH : DEFAULT_CHILD_HEIGHT;
+  const measured = Number(node?.measured?.[axis]);
+  if (Number.isFinite(measured) && measured > 0) return measured;
+  const direct = Number(node?.[axis]);
+  if (Number.isFinite(direct) && direct > 0) return direct;
+  const styled = Number(node?.style?.[axis]);
+  if (Number.isFinite(styled) && styled > 0) return styled;
+  return fallback;
+}
+
+export function getGroupMinimumSize(memberNodes: SizableNode[] | null | undefined, {
+  minWidth = 260,
+  minHeight = 180,
+  paddingX = 24,
+  paddingY = 24,
+} = {}) {
+  let maxRight = 0;
+  let maxBottom = 0;
+
+  for (const node of memberNodes || []) {
+    const x = Number(node?.position?.x) || 0;
+    const y = Number(node?.position?.y) || 0;
+    maxRight = Math.max(maxRight, x + getNodeSize(node, 'width'));
+    maxBottom = Math.max(maxBottom, y + getNodeSize(node, 'height'));
+  }
+
+  return {
+    width: Math.max(minWidth, Math.ceil(maxRight + paddingX)),
+    height: Math.max(minHeight, Math.ceil(maxBottom + paddingY)),
+  };
+}