single-or-array-pattern

单项或数组模式

同时接受单项和数组，在顶部统一规范化，然后以统一方式处理。

快速参考

function create(itemOrItems: T | T[]): Promise<Result<void, E>> {
	const items = Array.isArray(itemOrItems) ? itemOrItems : [itemOrItems];
	// ... implementation works on items array
}

结构

1. 接受 T | T[] 作为参数类型
2. 在函数顶部使用 Array.isArray() 规范化
3. 所有逻辑都以数组为基础：只使用一条代码路径

function createServer(clientOrClients: Client | Client[], options?: Options) {
	const clients = Array.isArray(clientOrClients)
		? clientOrClients
		: [clientOrClients];

	// All real logic here, working with the array
	for (const client of clients) {
		// ...
	}
}

命名约定

参数	规范化后的变量
recordingOrRecordings	recordings
clientOrClients	clients
itemOrItems	items
paramsOrParamsArray	paramsArray

适用场景

适合：

• CRUD 操作（创建、更新、删除）
• 批处理 API
• 接受依赖项的工厂函数
• 任何“对一个或多个对象执行某操作”的场景

不适合：

• 单项和批量操作语义不同
• 返回类型差异很大
• 数组版本需要不同的选项

代码库示例

服务端工厂（packages/server/src/server.ts）

function createServer(
	clientOrClients: AnyWorkspaceClient | AnyWorkspaceClient[],
	options?: ServerOptions,
) {
	const clients = Array.isArray(clientOrClients)
		? clientOrClients
		: [clientOrClients];

	// All server setup logic directly here
	const workspaces: Record<string, AnyWorkspaceClient> = {};
	for (const client of clients) {
		workspaces[client.id] = client;
	}
	// ...
}

服务方法

delete: async (recordingOrRecordings) => {
  const recordings = Array.isArray(recordingOrRecordings)
    ? recordingOrRecordings
    : [recordingOrRecordings];
  const ids = recordings.map((r) => r.id);
  return tryAsync({
    try: () => store.bulkDelete(ids),
    catch: (error) => RecordingStoreError.MutationFailed({ cause: error }),
  });
},

RPC 修改操作

export const recordingKeys = defineKeys({
	delete: ['recordings', 'delete'],
});

type DeleteRecordingsInput = Recording | Recording[];

export const recordings = {
	delete: defineMutation({
		mutationKey: recordingKeys.delete,
		mutationFn: async (recordings: DeleteRecordingsInput) => {
			const recordingsArray = Array.isArray(recordings)
				? recordings
				: [recordings];

			for (const recording of recordingsArray) {
				services.blobs.audio.revokePlaybackUrl(recording.id);
			}

			const { error } = await services.recordings.delete(recordingsArray);
			if (error) return Err(error);
			return Ok(undefined);
		},
	}),
};

反模式

不要：为单项和数组分别编写函数

// Harder to maintain, users must remember two APIs
function createRecording(recording: Recording): Promise<...>;
function createRecordings(recordings: Recording[]): Promise<...>;

不要：强制所有情况都使用数组

// Awkward for single items
createRecordings([recording]); // Ugly

不要：在重载中重复逻辑

// BAD: Logic duplicated
function create(item: T) {
	return db.insert(item); // Duplicated
}
function create(items: T[]) {
	return db.bulkInsert(items); // Different code path
}

// GOOD: Single implementation
function create(itemOrItems: T | T[]) {
	const items = Array.isArray(itemOrItems) ? itemOrItems : [itemOrItems];
	return db.bulkInsert(items); // One code path
}

参考资料

• 完整文章：包含更多示例的详细说明