Initial Commit

packages/commerce/contacts/api-plugin-contacts/src/tree/build-tree.ts

@@ -0,0 +1,41 @@
+/**
+ * Typed subtree builder. Given a root `Group` and a flat list of its
+ * descendants (in arbitrary order), produces a nested `GroupTreeNode`
+ * forest rooted at the supplied group. Replaces the upstream port's
+ * `function buildTree(root: any, descendants: any[]): any`.
+ */
+
+import type { Group, GroupTreeNode } from "@suaveplan/contacts";
+
+/**
+ * Build a typed tree rooted at `root` from a flat `descendants` list.
+ * Children are derived by `parentId === root.id`; the result is
+ * deterministic insofar as the input order is deterministic — the
+ * caller is responsible for sorting descendants if a deterministic
+ * traversal order is required.
+ */
+export function buildTree(
+    root: Group,
+    descendants: readonly Group[]
+): GroupTreeNode {
+    const childrenByParent = new Map<string, Group[]>();
+    for (const d of descendants) {
+        const key =
+            d.parentId !== null && d.parentId !== undefined ? d.parentId : "";
+        const bucket = childrenByParent.get(key);
+        if (bucket === undefined) {
+            childrenByParent.set(key, [d]);
+        } else {
+            bucket.push(d);
+        }
+    }
+    return walk(root, childrenByParent);
+}
+
+function walk(node: Group, byParent: Map<string, Group[]>): GroupTreeNode {
+    const children = byParent.get(node.id) ?? [];
+    return {
+        group: node,
+        children: children.map((child) => walk(child, byParent)),
+    };
+}