优化数据库读写

tests/api-dedup.test.mjs

@@ -0,0 +1,25 @@
+import assert from 'node:assert/strict';
+import { api } from '../src/client/api.mjs';
+
+const originalFetch = globalThis.fetch;
+let calls = 0;
+let release;
+globalThis.fetch = async () => {
+  calls += 1;
+  await new Promise(resolve => { release = resolve; });
+  return new Response(JSON.stringify({ ok: true, calls }), { status: 200, headers: { 'Content-Type': 'application/json' } });
+};
+
+try {
+  const first = api('/api/large-ledger');
+  const second = api('/api/large-ledger');
+  await Promise.resolve();
+  assert.equal(calls, 1, '并发的相同 GET 请求应只发送一次');
+  release();
+  assert.deepEqual(await first, { ok: true, calls: 1 });
+  assert.deepEqual(await second, { ok: true, calls: 1 });
+} finally {
+  globalThis.fetch = originalFetch;
+}
+
+console.log('API read deduplication tests passed');