Update preview.js to handle draft previews conditionally

Author: rkunjappan

js/source/preview.js

@@ -2,12 +2,33 @@ import {ARTICLE_UPDATE_SUBSCRIPTION, PantheonClient, PublishingLevel} from "@pan
 
 const params = new URLSearchParams(window.location.search);
 const documentId = drupalSettings.path.currentPath.split('/')[3];
+const publishingLevelParam = params.get('publishingLevel');
+const explicitVersionId = params.get('versionId');
 
 const pantheonClient = new PantheonClient({
     siteId: window.drupalSettings.pantheon_content_publisher.site_id,
     token: 'pcc_grant ' + params.get('pccGrant')
 });
 
+pantheonClient.apolloClient.subscribe({
+    query: ARTICLE_UPDATE_SUBSCRIPTION,
+    variables: {
+        id: documentId,
+        contentType: "TREE_PANTHEON_V2",
+        publishingLevel: PublishingLevel.REALTIME,
+    },
+})
+.subscribe({
+    next: ({ data }) => {
+        if (!data) return;
+        // const entryTitle = document.querySelector('h1');
+        // entryTitle.innerHTML = article.title;
+
+        const previewContentContainer = document.getElementById('pantheon-content-publisher-preview');
+        previewContentContainer.innerHTML = '';
+        previewContentContainer.appendChild(generateHTMLFromJSON(JSON.parse(data.article.content)));
+    },
+});
 
 function fetchAndRenderDraftPreview() {
     try {
@@ -48,25 +69,10 @@ function fetchAndRenderDraftPreview() {
     }
 }
 
-pantheonClient.apolloClient.subscribe({
-    query: ARTICLE_UPDATE_SUBSCRIPTION,
-    variables: {
-        id: documentId,
-        contentType: "TREE_PANTHEON_V2",
-        publishingLevel: PublishingLevel.REALTIME,
-    },
-})
-.subscribe({
-    next: ({ data }) => {
-        if (!data) return;
-        // const entryTitle = document.querySelector('h1');
-        // entryTitle.innerHTML = article.title;
-
-        const previewContentContainer = document.getElementById('pantheon-content-publisher-preview');
-        previewContentContainer.innerHTML = '';
-        previewContentContainer.appendChild(generateHTMLFromJSON(JSON.parse(data.article.content)));
-    },
-});
+if (publishingLevelParam === 'DRAFT' || VersionId) {
+   
+    fetchAndRenderDraftPreview();
+}
 
 function generateHTMLFromJSON(json, parentElement = null) {
     const createElement = (tag, attrs = {}, styles = {}, content = '') => {