60 lines
1.6 KiB
TypeScript
60 lines
1.6 KiB
TypeScript
/**
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* 地区数据模块级单例缓存。
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* 首次调用时 fetch /region.csv 并构建 idMap 和 parentMap，
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* 后续调用直接返回缓存，SPA 生命周期内只加载一次。
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*/
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interface RegionItem {
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id: number;
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parentId: number;
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level: number;
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name: string;
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}
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interface RegionCache {
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/** id → RegionItem，用于表格列的 id→name 转换 */
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idMap: Map<number, RegionItem>;
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/** parentId → children[]，用于省/市/区下拉联动 O(1) 查找 */
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parentMap: Map<number, RegionItem[]>;
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/** 所有地区平铺数组 */
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list: RegionItem[];
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}
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let _cache: RegionCache | null = null;
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function parseCSV(text: string): RegionItem[] {
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const lines = text.split("\n").filter((l) => l.trim());
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const headers = lines[0].split(",").map((h) => h.trim());
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return lines.slice(1).map((line) => {
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const cols = line.split(",").map((c) => c.trim());
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const obj: any = {};
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headers.forEach((h, i) => {
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obj[h] = h === "name" ? cols[i] : Number(cols[i]);
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});
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return obj as RegionItem;
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});
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}
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export async function useRegionCache(): Promise<RegionCache> {
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if (_cache) return _cache;
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const res = await fetch("/region.csv");
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if (!res.ok) throw new Error("地区数据加载失败");
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const text = await res.text();
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const list = parseCSV(text);
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const idMap = new Map<number, RegionItem>();
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const parentMap = new Map<number, RegionItem[]>();
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for (const item of list) {
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idMap.set(item.id, item);
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if (!parentMap.has(item.parentId)) {
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parentMap.set(item.parentId, []);
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}
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parentMap.get(item.parentId)!.push(item);
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}
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_cache = { idMap, parentMap, list };
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return _cache;
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}
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