fix operation position calculation

Author: timsuchanek

packages/graphql-playground-react/package.json

@@ -1,6 +1,6 @@
 {
   "name": "graphql-playground-react",
-  "version": "1.5.4",
+  "version": "1.5.5",
   "main": "./lib/lib.js",
   "typings": "./lib/lib.d.ts",
   "description": "GraphQL IDE for better development workflows (GraphQL Subscriptions, interactive docs & collaboration).",

packages/graphql-playground-react/src/state/sessions/sagas.ts

@@ -81,7 +81,11 @@ function* runQueryAtPosition(action) {
   if (session.operations) {
     let operationName
     session.operations.forEach((operation: any) => {
-      if (operation.loc.start <= position && operation.loc.end >= position) {
+      if (
+        operation.loc &&
+        operation.loc.start <= position &&
+        operation.loc.end >= position
+      ) {
         operationName = operation.name && operation.name.value
       }
     })