phonic
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JavaScript
;
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
return new (P || (P = Promise))(function (resolve, reject) {
function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
step((generator = generator.apply(thisArg, _arguments || [])).next());
});
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.requestWithRetries = requestWithRetries;
const INITIAL_RETRY_DELAY = 1000; // in milliseconds
const MAX_RETRY_DELAY = 60000; // in milliseconds
const DEFAULT_MAX_RETRIES = 2;
const JITTER_FACTOR = 0.2; // 20% random jitter
function addPositiveJitter(delay) {
// Generate a random value between 0 and +JITTER_FACTOR
const jitterMultiplier = 1 + Math.random() * JITTER_FACTOR;
return delay * jitterMultiplier;
}
function addSymmetricJitter(delay) {
// Generate a random value in a JITTER_FACTOR-sized percentage range around delay
const jitterMultiplier = 1 + (Math.random() - 0.5) * JITTER_FACTOR;
return delay * jitterMultiplier;
}
function getRetryDelayFromHeaders(response, retryAttempt) {
// Check for Retry-After header first (RFC 7231), with no jitter
const retryAfter = response.headers.get("Retry-After");
if (retryAfter) {
// Parse as number of seconds...
const retryAfterSeconds = parseInt(retryAfter, 10);
if (!isNaN(retryAfterSeconds) && retryAfterSeconds > 0) {
return Math.min(retryAfterSeconds * 1000, MAX_RETRY_DELAY);
}
// ...or as an HTTP date; both are valid
const retryAfterDate = new Date(retryAfter);
if (!isNaN(retryAfterDate.getTime())) {
const delay = retryAfterDate.getTime() - Date.now();
if (delay > 0) {
return Math.min(Math.max(delay, 0), MAX_RETRY_DELAY);
}
}
}
// Then check for industry-standard X-RateLimit-Reset header, with positive jitter
const rateLimitReset = response.headers.get("X-RateLimit-Reset");
if (rateLimitReset) {
const resetTime = parseInt(rateLimitReset, 10);
if (!isNaN(resetTime)) {
// Assume Unix timestamp in epoch seconds
const delay = resetTime * 1000 - Date.now();
if (delay > 0) {
return addPositiveJitter(Math.min(delay, MAX_RETRY_DELAY));
}
}
}
// Fall back to exponential backoff, with symmetric jitter
return addSymmetricJitter(Math.min(INITIAL_RETRY_DELAY * Math.pow(2, retryAttempt), MAX_RETRY_DELAY));
}
function requestWithRetries(requestFn_1) {
return __awaiter(this, arguments, void 0, function* (requestFn, maxRetries = DEFAULT_MAX_RETRIES) {
let response = yield requestFn();
for (let i = 0; i < maxRetries; ++i) {
if ([408, 429].includes(response.status) || response.status >= 500) {
// Get delay with appropriate jitter applied
const delay = getRetryDelayFromHeaders(response, i);
yield new Promise((resolve) => setTimeout(resolve, delay));
response = yield requestFn();
}
else {
break;
}
}
return response;
});
}