phase-6: typescript introduction

server/market/YahooClient.ts

@@ -0,0 +1,42 @@
+import YahooFinance from 'yahoo-finance2';
+
+export class YahooClient {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  private yf: any;
+
+  constructor() {
+    this.yf = new (YahooFinance as unknown as new (opts: object) => unknown)({
+      suppressNotices: ['yahooSurvey'],
+    });
+  }
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  async fetchSummary(ticker: string, retries = 3, backoff = 1000): Promise<any> {
+    for (let i = 0; i < retries; i++) {
+      try {
+        return await (this.yf as any).quoteSummary(ticker, {
+          modules: [
+            'assetProfile',
+            'financialData',
+            'defaultKeyStatistics',
+            'price',
+            'summaryDetail',
+          ],
+        });
+      } catch (error) {
+        if (i === retries - 1) throw error;
+        await new Promise<void>((res) => setTimeout(res, backoff * (i + 1)));
+      }
+    }
+  }
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  async fetchCalendarEvents(ticker: string): Promise<any | null> {
+    try {
+      const r = await (this.yf as any).quoteSummary(ticker, { modules: ['calendarEvents'] });
+      return r.calendarEvents ?? null;
+    } catch {
+      return null;
+    }
+  }
+}