work on navbar

web/static/src/ts/widgets/widget.ts

@@ -2,3 +2,23 @@ import { BaseWidget } from "../core/base_widget";
 import { Env } from "../env";
 
 export class Widget<Props, State> extends BaseWidget<Env, Props, State> {}
+
+// TODO: move this to PureComponent in core
+export class PureWidget<Props, State> extends Widget<Props, State> {
+  shouldUpdate(nextProps: Props): boolean {
+    for (let k in nextProps) {
+      if (nextProps[k] !== this.props[k]) {
+        return true;
+      }
+    }
+    return false;
+  }
+  async updateState(nextState: Partial<State>) {
+    for (let k in nextState) {
+      if (nextState[k] !== this.state[k]) {
+        return;
+      }
+    }
+    return super.updateState(nextState);
+  }
+}