[Beta] Sandpack bundler improvements (#5164)

* cache babel assets

* Update SandpackRoot.tsx

* Update NavigationBar.tsx

* Update SandpackRoot.tsx

* Update 7 files

* Update 6 files

* Update 6 files

* Update LoadingOverlay.tsx

* Update Preview.tsx

* Update LoadingOverlay.tsx

* Update 4 files

* Update beta/src/components/MDX/Sandpack/LoadingOverlay.tsx

Co-authored-by: Shanmughapriyan S <priyanshan03@gmail.com>

* Update sandpack.css

* Update Preview.tsx and SandpackRoot.tsx

* Update 3 files

* Update ErrorMessage.tsx and Preview.tsx

* Update Preview.tsx

* Update SandpackRoot.tsx

* Update Preview.tsx

Co-authored-by: Shanmughapriyan S <priyanshan03@gmail.com>

beta/src/components/MDX/Sandpack/ErrorMessage.tsx

@@ -10,13 +10,13 @@ interface ErrorType {
   path?: string;
 }
 
-export function Error({error}: {error: ErrorType}) {
+export function ErrorMessage({error, ...props}: {error: ErrorType}) {
   const {message, title} = error;
 
   return (
-    <div className={'bg-white border-2 border-red-40 rounded-lg p-6'}>
+    <div className="bg-white border-2 border-red-40 rounded-lg p-6" {...props}>
       <h2 className="text-red-40 text-xl mb-4">{title || 'Error'}</h2>
-      <pre className="text-secondary whitespace-pre-wrap break-words">
+      <pre className="text-secondary whitespace-pre-wrap break-words leading-tight">
         {message}
       </pre>
     </div>

beta/src/components/MDX/Sandpack/LoadingOverlay.tsx

@@ -0,0 +1,142 @@
+import {useState} from 'react';
+
+import {
+  LoadingOverlayState,
+  OpenInCodeSandboxButton,
+  useSandpack,
+} from '@codesandbox/sandpack-react';
+import {useEffect} from 'react';
+
+const FADE_ANIMATION_DURATION = 200;
+
+export const LoadingOverlay = ({
+  clientId,
+  dependenciesLoading,
+  forceLoading,
+}: {
+  clientId: string;
+  dependenciesLoading: boolean;
+  forceLoading: boolean;
+} & React.HTMLAttributes<HTMLDivElement>): JSX.Element | null => {
+  const loadingOverlayState = useLoadingOverlayState(
+    clientId,
+    dependenciesLoading,
+    forceLoading
+  );
+
+  if (loadingOverlayState === 'HIDDEN') {
+    return null;
+  }
+
+  if (loadingOverlayState === 'TIMEOUT') {
+    return (
+      <div className="sp-overlay sp-error">
+        <div className="sp-error-message">
+          Unable to establish connection with the sandpack bundler. Make sure
+          you are online or try again later. If the problem persists, please
+          report it via{' '}
+          <a
+            className="sp-error-message"
+            href="mailto:hello@codesandbox.io?subject=Sandpack Timeout Error">
+            email
+          </a>{' '}
+          or submit an issue on{' '}
+          <a
+            className="sp-error-message"
+            href="https://github.com/codesandbox/sandpack/issues"
+            rel="noreferrer noopener"
+            target="_blank">
+            GitHub.
+          </a>
+        </div>
+      </div>
+    );
+  }
+
+  const stillLoading =
+    loadingOverlayState === 'LOADING' || loadingOverlayState === 'PRE_FADING';
+
+  return (
+    <div
+      className="sp-overlay sp-loading"
+      style={{
+        opacity: stillLoading ? 1 : 0,
+        transition: `opacity ${FADE_ANIMATION_DURATION}ms ease-out`,
+      }}>
+      <div className="sp-cube-wrapper" title="Open in CodeSandbox">
+        <OpenInCodeSandboxButton />
+        <div className="sp-cube">
+          <div className="sp-sides">
+            <div className="top" />
+            <div className="right" />
+            <div className="bottom" />
+            <div className="left" />
+            <div className="front" />
+            <div className="back" />
+          </div>
+        </div>
+      </div>
+    </div>
+  );
+};
+
+const useLoadingOverlayState = (
+  clientId: string,
+  dependenciesLoading: boolean,
+  forceLoading: boolean
+): LoadingOverlayState => {
+  const {sandpack, listen} = useSandpack();
+  const [state, setState] = useState<LoadingOverlayState>('HIDDEN');
+
+  if (state !== 'LOADING' && forceLoading) {
+    setState('LOADING');
+  }
+
+  /**
+   * Sandpack listener
+   */
+  const sandpackIdle = sandpack.status === 'idle';
+  useEffect(() => {
+    const unsubscribe = listen((message) => {
+      if (message.type === 'done') {
+        setState((prev) => {
+          return prev === 'LOADING' ? 'PRE_FADING' : 'HIDDEN';
+        });
+      }
+    }, clientId);
+
+    return () => {
+      unsubscribe();
+    };
+  }, [listen, clientId, sandpackIdle]);
+
+  /**
+   * Fading transient state
+   */
+  useEffect(() => {
+    let fadeTimeout: ReturnType<typeof setTimeout>;
+
+    if (state === 'PRE_FADING' && !dependenciesLoading) {
+      setState('FADING');
+    } else if (state === 'FADING') {
+      fadeTimeout = setTimeout(
+        () => setState('HIDDEN'),
+        FADE_ANIMATION_DURATION
+      );
+    }
+
+    return () => {
+      clearTimeout(fadeTimeout);
+    };
+  }, [state, dependenciesLoading]);
+
+  if (sandpack.status === 'timeout') {
+    return 'TIMEOUT';
+  }
+
+  if (sandpack.status !== 'running') {
+    return 'HIDDEN';
+  }
+
+  return state;
+};

beta/src/components/MDX/Sandpack/NavigationBar.tsx

@@ -22,7 +22,6 @@ import {DownloadButton} from './DownloadButton';
 import {IconChevron} from '../../Icon/IconChevron';
 import {Listbox} from '@headlessui/react';
 
-// TODO: Replace with real useEvent.
 export function useEvent(fn: any): any {
   const ref = useRef(null);
   useInsertionEffect(() => {
@@ -94,9 +93,20 @@ export function NavigationBar({providedFiles}: {providedFiles: Array<string>}) {
   }, [isMultiFile]);
 
   const handleReset = () => {
-    if (confirm('Reset all your edits too?')) {
+    /**
+     * resetAllFiles must come first, otherwise
+     * the previous content will appears for a second
+     * when the iframe loads.
+     *
+     * Plus, it should only prompts if there's any file changes
+     */
+    if (
+      sandpack.editorState === 'dirty' &&
+      confirm('Reset all your edits too?')
+    ) {
       sandpack.resetAllFiles();
     }
+
     refresh();
   };
 

beta/src/components/MDX/Sandpack/Preview.tsx

@@ -3,26 +3,17 @@
  */
 
 /* eslint-disable react-hooks/exhaustive-deps */
-import {useRef, useState, useEffect, useMemo} from 'react';
-import {
-  useSandpack,
-  LoadingOverlay,
-  SandpackStack,
-} from '@codesandbox/sandpack-react';
+import {useRef, useState, useEffect, useMemo, useId} from 'react';
+import {useSandpack, SandpackStack} from '@codesandbox/sandpack-react';
 import cn from 'classnames';
-import {Error} from './Error';
+import {ErrorMessage} from './ErrorMessage';
 import {SandpackConsole} from './Console';
 import type {LintDiagnostic} from './useSandpackLint';
-
-/**
- * TODO: can we use React.useId?
- */
-const generateRandomId = (): string =>
-  Math.floor(Math.random() * 10000).toString();
+import {CSSProperties} from 'react';
+import {LoadingOverlay} from './LoadingOverlay';
 
 type CustomPreviewProps = {
   className?: string;
-  customStyle?: Record<string, unknown>;
   isExpanded: boolean;
   lintErrors: LintDiagnostic;
 };
@@ -40,13 +31,13 @@ function useDebounced(value: any): any {
 }
 
 export function Preview({
-  customStyle,
   isExpanded,
   className,
   lintErrors,
 }: CustomPreviewProps) {
   const {sandpack, listen} = useSandpack();
-  const [isReady, setIsReady] = useState(false);
+  const [bundlerIsReady, setBundlerIsReady] = useState(false);
+  const [showLoading, setShowLoading] = useState(false);
   const [iframeComputedHeight, setComputedAutoHeight] = useState<number | null>(
     null
   );
@@ -95,7 +86,7 @@ export function Preview({
   // It changes too fast, causing flicker.
   const error = useDebounced(rawError);
 
-  const clientId = useRef<string>(generateRandomId());
+  const clientId = useId();
   const iframeRef = useRef<HTMLIFrameElement | null>(null);
 
   // SandpackPreview immediately registers the custom screens/components so the bundler does not render any of them
@@ -104,46 +95,54 @@ export function Preview({
   errorScreenRegisteredRef.current = true;
   loadingScreenRegisteredRef.current = true;
 
+  const sandpackIdle = sandpack.status === 'idle';
+
   useEffect(function createBundler() {
     const iframeElement = iframeRef.current!;
-    registerBundler(iframeElement, clientId.current);
+    registerBundler(iframeElement, clientId);
 
     return () => {
-      unregisterBundler(clientId.current);
+      unregisterBundler(clientId);
     };
   }, []);
 
   useEffect(
     function bundlerListener() {
-      const unsubscribe = listen((message: any) => {
+      let timeout: ReturnType<typeof setTimeout>;
+
+      const unsubscribe = listen((message) => {
         if (message.type === 'resize') {
           setComputedAutoHeight(message.height);
         } else if (message.type === 'start') {
           if (message.firstLoad) {
-            setIsReady(false);
+            setBundlerIsReady(false);
           }
+
+          /**
+           * The spinner component transition might be longer than
+           * the bundler loading, so we only show the spinner if
+           * it takes more than 1s to load the bundler.
+           */
+          timeout = setTimeout(() => {
+            setShowLoading(true);
+          }, 500);
         } else if (message.type === 'done') {
-          setIsReady(true);
+          setBundlerIsReady(true);
+          setShowLoading(false);
+          clearTimeout(timeout);
         }
-      }, clientId.current);
+      }, clientId);
 
       return () => {
-        setIsReady(false);
+        clearTimeout(timeout);
+        setBundlerIsReady(false);
         setComputedAutoHeight(null);
         unsubscribe();
       };
     },
-    [status === 'idle']
+    [sandpackIdle]
   );
 
-  const overrideStyle = error
-    ? {
-        // Don't collapse errors
-        maxHeight: undefined,
-      }
-    : null;
-  const hideContent = !isReady || error;
-
   // WARNING:
   // The layout and styling here is convoluted and really easy to break.
   // If you make changes to it, you need to test different cases:
@@ -159,67 +158,68 @@ export function Preview({
   // - It should work on mobile.
   // The best way to test it is to actually go through some challenges.
 
+  const hideContent = error || !iframeComputedHeight || !bundlerIsReady;
+
+  const iframeWrapperPosition = (): CSSProperties => {
+    if (hideContent) {
+      return {position: 'relative'};
+    }
+
+    if (isExpanded) {
+      return {position: 'sticky', top: '2em'};
+    }
+
+    return {};
+  };
+
   return (
-    <SandpackStack
-      className={className}
-      style={{
-        // TODO: clean up this mess.
-        ...customStyle,
-        ...overrideStyle,
-      }}>
+    <SandpackStack className={className}>
       <div
         className={cn(
           'p-0 sm:p-2 md:p-4 lg:p-8 bg-card dark:bg-wash-dark h-full relative md:rounded-b-lg lg:rounded-b-none',
           // Allow content to be scrolled if it's too high to fit.
           // Note we don't want this in the expanded state
           // because it breaks position: sticky (and isn't needed anyway).
-          !isExpanded && (error || isReady) ? 'overflow-auto' : null
+          !isExpanded && (error || bundlerIsReady) ? 'overflow-auto' : null
         )}>
-        <div
-          style={{
-            padding: 'initial',
-            position: hideContent
-              ? 'relative'
-              : isExpanded
-              ? 'sticky'
-              : undefined,
-            top: isExpanded ? '2rem' : undefined,
-          }}>
+        <div style={iframeWrapperPosition()}>
           <iframe
             ref={iframeRef}
             className={cn(
-              'rounded-t-none bg-white md:shadow-md sm:rounded-lg w-full max-w-full',
+              'rounded-t-none bg-white md:shadow-md sm:rounded-lg w-full max-w-full transition-opacity',
               // We can't *actually* hide content because that would
               // break calculating the computed height in the iframe
               // (which we're using for autosizing). This is noticeable
               // if you make a compiler error and then fix it with code
               // that expands the content. You want to measure that.
               hideContent
-                ? 'absolute opacity-0 pointer-events-none'
-                : 'opacity-100'
+                ? 'absolute opacity-0 pointer-events-none duration-75'
+                : 'opacity-100 duration-150'
             )}
             title="Sandbox Preview"
             style={{
-              height: iframeComputedHeight || '100%',
+              height: iframeComputedHeight || '15px',
               zIndex: isExpanded ? 'initial' : -1,
             }}
           />
         </div>
+
         {error && (
           <div
             className={cn(
-              'p-2',
+              'z-50',
               // This isn't absolutely positioned so that
               // the errors can also expand the parent height.
-              isExpanded ? 'sticky top-8' : null
+              isExpanded ? 'sticky top-8 ' : null
             )}>
-            <Error error={error} />
+            <ErrorMessage error={error} />
           </div>
         )}
+
         <LoadingOverlay
-          showOpenInCodeSandbox
-          clientId={clientId.current}
-          loading={!isReady && iframeComputedHeight === null}
+          clientId={clientId}
+          dependenciesLoading={!bundlerIsReady && iframeComputedHeight === null}
+          forceLoading={showLoading}
         />
       </div>
       <SandpackConsole visible={!error} />

beta/src/components/MDX/Sandpack/SandpackRoot.tsx

@@ -87,7 +87,8 @@ function SandpackRoot(props: SandpackProps) {
           autorun,
           initMode: 'user-visible',
           initModeObserverOptions: {rootMargin: '1400px 0px'},
-          bundlerURL: 'https://ac83f2d6.sandpack-bundler.pages.dev',
+          bundlerURL:
+            'https://71d9edc6.sandpack-bundler.pages.dev/?babel=minimal',
           logLevel: SandpackLogLevel.None,
         }}>
         <CustomPreset

beta/src/styles/sandpack.css

@@ -255,6 +255,12 @@ html.dark .sp-wrapper {
   @apply border-red-40;
 }
 
+.sandpack .sp-cm {
+  margin: 0px;
+  outline: none;
+  height: 100%;
+}
+
 .sp-code-editor .sp-cm .cm-scroller {
   overflow-x: hidden;
   overflow-y: auto;