Retry after certain Cloudflare errors (#991)

readme.md

@@ -367,7 +367,7 @@ Default:
 - limit: `2`
 - calculateDelay: `(attemptCount, retryOptions, error, computedValue) => computedValue`
 - methods: `GET` `PUT` `HEAD` `DELETE` `OPTIONS` `TRACE`
-- statusCodes: [`408`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/408) [`413`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/413) [`429`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/429) [`500`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/500) [`502`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/502) [`503`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/503) [`504`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/504)
+- statusCodes: [`408`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/408) [`413`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/413) [`429`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/429) [`500`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/500) [`502`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/502) [`503`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/503) [`504`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/504) [`521`](https://support.cloudflare.com/hc/en-us/articles/115003011431#521error) [`522`](https://support.cloudflare.com/hc/en-us/articles/115003011431#522error) [`524`](https://support.cloudflare.com/hc/en-us/articles/115003011431#524error)
 - maxRetryAfter: `undefined`
 - errorCodes: `ETIMEDOUT` `ECONNRESET` `EADDRINUSE` `ECONNREFUSED` `EPIPE` `ENOTFOUND` `ENETUNREACH` `EAI_AGAIN`
 

source/index.ts

@@ -21,7 +21,10 @@ const defaults: Defaults = {
 				500,
 				502,
 				503,
-				504
+				504,
+				521,
+				522,
+				524
 			],
 			errorCodes: [
 				'ETIMEDOUT',