Add option forceRevalidateOnReconnect to hard-revalidate when regaining a network connection

Author: notuxic

_internal/src/types.ts

@@ -72,6 +72,11 @@ export interface PublicConfiguration<
    * @defaultValue 5000
    */
   focusThrottleInterval: number
+  /**
+   * only revalidate once during a time span in milliseconds
+   * @defaultValue 5000
+   */
+  reconnectThrottleInterval: number
   /**
    * dedupe requests with the same key in this time span in milliseconds
    * @defaultValue 2000
@@ -116,6 +121,11 @@ export interface PublicConfiguration<
    * @link https://swr.vercel.app/docs/revalidation#disable-automatic-revalidations
    */
   revalidateIfStale: boolean
+  /**
+   * ignore `dedupingInterval` (but not `reconnectThrottleInterval`) when revalidating after regaining a network connection
+   * @defaultValue false
+   */
+  forceRevalidateOnReconnect: boolean
   /**
    * retry when fetcher has an error
    * @defaultValue true

_internal/src/utils/config.ts

@@ -58,11 +58,13 @@ export const defaultConfig: FullConfiguration = mergeObjects(
     revalidateOnFocus: true,
     revalidateOnReconnect: true,
     revalidateIfStale: true,
+    forceRevalidateOnReconnect: false,
     shouldRetryOnError: true,
 
     // timeouts
     errorRetryInterval: slowConnection ? 10000 : 5000,
     focusThrottleInterval: 5 * 1000,
+    reconnectThrottleInterval: 5 * 1000,
     dedupingInterval: 2 * 1000,
     loadingTimeout: slowConnection ? 5000 : 3000,
 

core/src/use-swr.ts

@@ -577,15 +577,16 @@ export const useSWRHandler = <Data = any, Error = any>(
     // Expose revalidators to global event listeners. So we can trigger
     // revalidation from the outside.
     let nextFocusRevalidatedAt = 0
+    let nextReconnectRevalidatedAt = 0
     const onRevalidate = (
       type: RevalidateEvent,
       opts: {
         retryCount?: number
         dedupe?: boolean
       } = {}
     ) => {
+      const now = Date.now()
       if (type == revalidateEvents.FOCUS_EVENT) {
-        const now = Date.now()
         if (
           getConfig().revalidateOnFocus &&
           now > nextFocusRevalidatedAt &&
@@ -595,8 +596,18 @@ export const useSWRHandler = <Data = any, Error = any>(
           softRevalidate()
         }
       } else if (type == revalidateEvents.RECONNECT_EVENT) {
-        if (getConfig().revalidateOnReconnect && isActive()) {
-          softRevalidate()
+        if (
+          getConfig().revalidateOnReconnect &&
+          now > nextReconnectRevalidatedAt &&
+          isActive()
+        ) {
+          nextReconnectRevalidatedAt = now + getConfig().reconnectThrottleInterval
+          if (getConfig().forceRevalidateOnReconnect) {
+            return revalidate()
+          }
+          else {
+            softRevalidate()
+          }
         }
       } else if (type == revalidateEvents.MUTATE_EVENT) {
         return revalidate()