Grabbed dndbeyond's source code

```
~/go/bin/sourcemapper -output ddb -jsurl https://media.dndbeyond.com/character-app/static/js/main.90aa78c5.js
```

ddb_main/tools/js/Shared/components/LoadingBlocker/LoadingBlocker.tsx

@@ -0,0 +1,59 @@
+import React from "react";
+
+import { AnimatedLoadingRingSvg } from "@dndbeyond/character-components/es";
+
+interface Props {
+  isFinished: boolean;
+  hideDelay: number;
+}
+interface State {
+  isVisible: boolean;
+}
+export default class LoadingBlocker extends React.PureComponent<Props, State> {
+  static defaultProps = {
+    hideDelay: 2000,
+  };
+
+  constructor(props: Props) {
+    super(props);
+
+    this.state = {
+      isVisible: !props.isFinished,
+    };
+  }
+
+  componentDidUpdate(
+    prevProps: Readonly<Props>,
+    prevState: Readonly<State>
+  ): void {
+    const { isFinished, hideDelay } = this.props;
+
+    if (!prevProps.isFinished && isFinished) {
+      setTimeout(() => {
+        this.setState({
+          isVisible: false,
+        });
+      }, hideDelay);
+    }
+  }
+
+  render() {
+    const { isVisible } = this.state;
+    const { isFinished } = this.props;
+
+    if (!isVisible) {
+      return null;
+    }
+
+    return (
+      <div
+        className={`ct-loading-blocker ${
+          isFinished ? " ct-loading-blocker--finished" : ""
+        }`}
+      >
+        <div className="ct-loading-blocker__logo" />
+        <AnimatedLoadingRingSvg className="ct-loading-blocker__anim" />
+      </div>
+    );
+  }
+}

ddb_main/tools/js/Shared/components/LoadingBlocker/index.ts

@@ -0,0 +1,4 @@
+import LoadingBlocker from "./LoadingBlocker";
+
+export default LoadingBlocker;
+export { LoadingBlocker };