getFilters: return immediately if filters are empty

src/client.ts

@@ -29,6 +29,7 @@ function getPool(): Pool {
 
 /** Get events from a NIP-01 filter. */
 function getFilters<K extends number>(filters: Filter<K>[], opts: GetFiltersOpts = {}): Promise<Event<K>[]> {
+  if (!filters.length) return Promise.resolve([]);
   return new Promise((resolve) => {
     let tid: number;
     const results: Event[] = [];

src/db/events.ts

@@ -108,6 +108,7 @@ async function getFilters<K extends number>(
   filters: DittoFilter<K>[],
   opts: GetFiltersOpts = {},
 ): Promise<Event<K>[]> {
+  if (!filters.length) return Promise.resolve([]);
   let query = filters.map(getFilterQuery).reduce((acc, curr) => acc.union(curr));
 
   if (typeof opts.limit === 'number') {