Ensure that ERD throws a warning before closing unsaved changes if open in a new tab. Fixes #6193

web/pgadmin/tools/erd/static/js/erd_tool/ERDCore.js

@@ -355,9 +355,14 @@ export default class ERDCore {
 
   zoomOut() {
     let model = this.getEngine().getModel();
-    let zoomLevel = model.getZoomLevel();
-    if(model && zoomLevel > 25) {
-      model.setZoomLevel(zoomLevel - 25);
+    if(model) {
+      let zoomLevel = model.getZoomLevel();
+      zoomLevel -= 25;
+      /* Don't go belo zoom level 10 */
+      if(zoomLevel <= 10) {
+        zoomLevel = 10;
+      }
+      model.setZoomLevel(zoomLevel);
       this.repaint();
     }
   }

web/pgadmin/tools/erd/static/js/erd_tool/ui_components/BodyWidget.jsx

@@ -235,6 +235,12 @@ export default class BodyWidget extends React.Component {
     if(this.props.params.gen) {
       await this.loadTablesData();
     }
+
+    window.addEventListener('beforeunload', this.onBeforeUnload.bind(this));
+  }
+
+  componentWillUnmount() {
+    window.removeEventListener('beforeunload', this.onBeforeUnload.bind(this));
   }
 
   componentDidUpdate() {
@@ -348,6 +354,15 @@ export default class BodyWidget extends React.Component {
     }
   }
 
+  onBeforeUnload(e) {
+    if(this.state.dirty) {
+      e.preventDefault();
+      e.returnValue = 'prevent';
+    } else {
+      delete e['returnValue'];
+    }
+  }
+
   onEditNode() {
     const selected = this.diagram.getSelectedNodes();
     if(selected.length == 1) {