45 lines
1.3 KiB
TypeScript
45 lines
1.3 KiB
TypeScript
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export type ParentLinkedRow = {
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id: string;
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parent_id?: string | null;
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};
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/**
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* 收集以 rootId 为根的整棵子树（包含根节点本身）。
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*
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* 说明：
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* - 仅依赖 (id, parent_id) 字段，便于在 Convex 与前端共用同一套遍历逻辑。
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* - 会做去重与环检测，避免异常数据导致死循环。
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*/
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export function collectSubtree<T extends ParentLinkedRow>(rows: readonly T[], rootId: string): T[] {
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const byParentId = new Map<string | null, T[]>();
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for (const row of rows) {
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const parentId = (row.parent_id ?? null) as string | null;
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const bucket = byParentId.get(parentId);
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if (bucket) bucket.push(row);
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else byParentId.set(parentId, [row]);
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}
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const root = rows.find((r) => r.id === rootId);
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if (!root) return [];
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const visited = new Set<string>();
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const stack: T[] = [root];
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const result: T[] = [];
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while (stack.length > 0) {
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const current = stack.pop()!;
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if (visited.has(current.id)) continue;
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visited.add(current.id);
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result.push(current);
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const children = byParentId.get(current.id) ?? [];
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// 倒序入栈，保持更接近“原列表顺序”的遍历结果（不影响正确性）
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for (let i = children.length - 1; i >= 0; i -= 1) {
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stack.push(children[i]!);
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}
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}
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return result;
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}
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