Show a proper error message on creating/updating an event

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

js/src/views/Event/Edit.vue

@@ -588,6 +588,7 @@ export default class EditEvent extends Vue {
     } catch (err) {
       this.saving = false;
       console.error(err);
+      this.handleError(err);
     }
   }
 
@@ -615,7 +616,7 @@ export default class EditEvent extends Vue {
       });
     } catch (err) {
       this.saving = false;
-      console.error(err);
+      this.handleError(err);
     }
   }
 
@@ -627,6 +628,16 @@ export default class EditEvent extends Vue {
       : this.$i18n.t("The event has been updated")) as string;
   }
 
+  private handleError(err: any) {
+    console.error(err);
+
+    if (err.graphQLErrors !== undefined) {
+      err.graphQLErrors.forEach(({ message }: { message: string }) => {
+        this.$notifier.error(message);
+      });
+    }
+  }
+
   /**
    * Put in cache the updated or created event.
    * If the event is not a draft anymore, also put in cache the participation