fix(t2viz): string escape should only escape field (#325)

Signed-off-by: Yulong Ruan <[email protected]>

CHANGELOG.md

@@ -14,6 +14,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - feat: check all required agents before enabling index pattern selection for text to visualization([313](https://github.com/opensearch-project/dashboards-assistant/pull/313))
 - fix: pass data source id for alert summary/insight([#321](https://github.com/opensearch-project/dashboards-assistant/pull/321))
 - feat: support navigating to discover in alerting popover([#316](https://github.com/opensearch-project/dashboards-assistant/pull/316))
+- fix: incorrect string escaping of vega schema([325](https://github.com/opensearch-project/dashboards-assistant/pull/325))
 
 ### 📈 Features/Enhancements
 

public/components/visualization/text2vega.ts

@@ -108,7 +108,8 @@ export class Text2Vega {
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     const escapeField = (json: any, field: string) => {
       if (json[field]) {
-        if (typeof json[field] === 'string') {
+        // Only escape field which name is 'field'
+        if (typeof json[field] === 'string' && field === 'field') {
           json[field] = json[field].replace(/\./g, '\\.');
         }
         if (typeof json[field] === 'object') {
@@ -132,6 +133,7 @@ export class Text2Vega {
 
     // need to escape field: geo.city -> field: geo\\.city
     escapeField(res, 'encoding');
+    escapeField(res, 'layer');
     return res;
   }