feat: mutual friend graph (#1491)

src/shared/utils/index.js

@@ -17,3 +17,5 @@ export * from './location';
 export * from './invite';
 export * from './world';
 export * from './memos';
+export * from './throttle';
+export * from './retry';

src/shared/utils/retry.js

@@ -0,0 +1,24 @@
+export async function executeWithBackoff(fn, options = {}) {
+    const {
+        maxRetries = 5,
+        baseDelay = 1000,
+        shouldRetry = () => true
+    } = options;
+
+    async function attempt(remaining) {
+        try {
+            return await fn();
+        } catch (err) {
+            if (remaining <= 0 || !shouldRetry(err)) {
+                throw err;
+            }
+            const delay =
+                baseDelay *
+                Math.pow(2, (options.maxRetries || maxRetries) - remaining);
+            await new Promise((resolve) => setTimeout(resolve, delay));
+            return attempt(remaining - 1);
+        }
+    }
+
+    return attempt(maxRetries);
+}

src/shared/utils/throttle.js

@@ -0,0 +1,28 @@
+export function createRateLimiter({ limitPerInterval, intervalMs }) {
+    const stamps = [];
+
+    async function throttle() {
+        const now = Date.now();
+        while (stamps.length && now - stamps[0] > intervalMs) {
+            stamps.shift();
+        }
+        if (stamps.length >= limitPerInterval) {
+            const wait = intervalMs - (now - stamps[0]);
+            await new Promise((resolve) => setTimeout(resolve, wait));
+        }
+        stamps.push(Date.now());
+    }
+
+    return {
+        async schedule(fn) {
+            await throttle();
+            return fn();
+        },
+        async wait() {
+            await throttle();
+        },
+        clear() {
+            stamps.length = 0;
+        }
+    };
+}