fix: add sdk as script

lib/previewRequest.ts

@@ -10,34 +10,38 @@ import ContentstackLivePreview from "@contentstack/live-preview-utils";
 export async function previewRequest<T>(
   query: string | DocumentNode,
   variables?: {}
-): Promise<Data<T>> {
-  try {
-    const hash = ContentstackLivePreview.hash;
+): Promise<Data<T> | null> {
+  const hash = ContentstackLivePreview.hash;
 
-    if (!env.CMS_PREVIEW_URL || !env.CMS_PREVIEW_TOKEN) {
-      throw new Error("No preview URL");
-    }
-    const headers = new Headers();
-
-    headers.append("access_token", env.CMS_ACCESS_TOKEN);
-    headers.append("Content-Type", "application/json");
-    headers.append("preview_token", env.CMS_PREVIEW_TOKEN);
-    headers.append("live_preview", hash);
-
-    const response = await fetch(env.CMS_PREVIEW_URL.toString(), {
-      method: "POST",
-      headers,
-      body: JSON.stringify({
-        query,
-        variables,
-      }),
-    });
-
-    const { data } = await response.json();
-
-    return data as Data<T>;
-  } catch (error) {
-    console.error(error);
-    throw new Error("Something went wrong");
+  if (!hash) {
+    return null;
   }
+
+  if (!env.CMS_PREVIEW_URL || !env.CMS_PREVIEW_TOKEN) {
+    throw new Error("No preview URL");
+  }
+  const headers = new Headers();
+
+  headers.append("access_token", env.CMS_ACCESS_TOKEN);
+  headers.append("Content-Type", "application/json");
+  headers.append("preview_token", env.CMS_PREVIEW_TOKEN);
+  headers.append("live_preview", hash);
+
+  const response = await fetch(env.CMS_PREVIEW_URL, {
+    method: "POST",
+    headers,
+    body: JSON.stringify({
+      query,
+      variables,
+    }),
+  });
+
+  if (!response.ok) {
+    console.log(response);
+    throw new Error("Cound not fetch preview content");
+  }
+
+  const { data } = await response.json();
+
+  return data as Data<T>;
 }