handle invalid perspective format

packages/web/src/tabs/PerspectiveTab.svelte

@@ -45,6 +45,7 @@
   import { registerFileCommands } from '../commands/stdCommands';
   import _ from 'lodash';
   import ToolStripSaveButton from '../buttons/ToolStripSaveButton.svelte';
+  import ErrorInfo from '../elements/ErrorInfo.svelte';
 
   export let tabid;
   export let conid;
@@ -52,6 +53,8 @@
   export let schemaName;
   export let pureName;
 
+  let isFormatError;
+
   export const activator = createActivator('PerspectiveTab', true);
 
   $: connection = useConnectionInfo({ conid });
@@ -88,7 +91,11 @@
   const { editorState, editorValue, setEditorData } = useEditorData({
     tabid,
     onInitialData: value => {
+      if (!value.nodes) {
+        isFormatError = true;
+      } else {
         dispatchModel({ type: 'reset', value });
+      }
       invalidateCommands();
     },
   });
@@ -110,6 +117,9 @@
 </script>
 
 <ToolStripContainer>
+  {#if isFormatError}
+    <ErrorInfo message="Invalid perspective format, please create new perspective" alignTop />
+  {:else}
     <PerspectiveView
       {conid}
       {database}
@@ -132,6 +142,7 @@
       {cache}
       {loadedCounts}
     />
+  {/if}
 
   <svelte:fragment slot="toolstrip">
     <ToolStripCommandButton