Add parseBigInt as an option in fetchJson

ui/packages/lib/src/utils/fetchJson.js

@@ -50,7 +50,7 @@ const fetchData = async (url, authCtx, options) => {
 export default async (url, authCtx, options = {}) => {
   return fetchData(url, authCtx, options)
     .then(response =>
-      parseJson(response).then(result => {
+      parseJson(response, !!options.parseBigInt).then(result => {
         var headers = {};
         for (var pair of response.headers.entries()) {
           headers[pair[0]] = pair[1];

ui/packages/lib/src/utils/parseJson.js

@@ -1,11 +1,15 @@
 const jsonBig = require(`json-bigint`);
 
-export const parseJson = response => {
+const parseJsonHandleBigInt = (response, parseBigInt) => {
+  return parseBigInt
+    ? response.text().then(text => jsonBig.parse(text))
+    : response.json();
+}
+
+export const parseJson = (response, parseBigInt) => {
   // using the json-bigint library to parse the data instead of the Response.json() Web API,
   // to parse BigInt without losing precision.
-  return response.text().then(
-    text => jsonBig.parse(text)
-  ).catch(error => {
+  return parseJsonHandleBigInt(response, parseBigInt).catch(error => {
     // for responses without body
     if (error.name === "SyntaxError") {
       return {};