Function insertAfter

packages/react-stately/src/data/useTreeData.ts:324–334

(key: Key, ...values: T[])

      this.insert(parentNode?.key ?? null, index, ...values);
    },
    insertAfter(key: Key, ...values: T[]): void {
      let node = nodeMap.get(key);
      if (!node) {
        return;
      }

      let parentNode = nodeMap.get(node.parentKey!);
      let nodes = parentNode ? parentNode.children : items;
      let index = nodes!.indexOf(node);
      this.insert(parentNode?.key ?? null, index + 1, ...values);
    },
    prepend(parentKey: Key | null, ...values: T[]) {
      this.insert(parentKey, 0, ...values);
    },