feat: Forward operation in StackLink.request() on Network error

On the Flagship app we want to serve `.query()` request using the
`StackLink` when the device is connected, but we want to fallback to
the `PouchLink` when we detect a connection loss

In previous commit we tried pro-actively detect for connexion loss by
calling an `isOnline()` method before processing the request

But we want to also catch network errors when the `isOnline()` methods
fails to detect connection loss, then we also fallback to the next
`Link`

Author: Ldoppea

packages/cozy-client/src/StackLink.js

@@ -5,6 +5,7 @@ import CozyLink from './CozyLink'
 import { DOCTYPE_FILES } from './const'
 import { BulkEditError } from './errors'
 import logger from './logger'
+import { isReactNativeOfflineError } from './utils'
 
 /**
  *
@@ -84,10 +85,17 @@ export default class StackLink extends CozyLink {
       return forward(operation)
     }
 
-    if (operation.mutationType) {
-      return this.executeMutation(operation, result, forward)
+    try {
+      if (operation.mutationType) {
+        return await this.executeMutation(operation, result, forward)
+      }
+      return await this.executeQuery(operation)
+    } catch (err) {
+      if (isReactNativeOfflineError(err)) {
+        return forward(operation)
+      }
+      throw err
     }
-    return this.executeQuery(operation)
   }
 
   async persistData(data, forward) {

packages/cozy-client/src/utils.js

@@ -68,3 +68,15 @@ export const hasQueriesBeenLoaded = queriesResults => {
     hasQueryBeenLoaded(queryResult)
   )
 }
+
+/**
+ * Check is the error is about ReactNative not having access to internet
+ *
+ * @param {Error} err - The error to check
+ * @returns {boolean} True if the error is a network error, otherwise false
+ */
+export const isReactNativeOfflineError = err => {
+  // This error message is specific to ReactNative
+  // Network errors on a browser would produce another error.message
+  return err.message === 'Network request failed'
+}