fix: accessibility issue in tabs

sandpack-react/package.json

@@ -39,7 +39,6 @@
     "lint": "eslint '**/*.ts?(x)' --fix",
     "build": "rollup -c",
     "build:publish": "yarn build",
-    "start": "tsc -p tsconfig.esm.json --watch",
     "dev": "storybook dev -p 6006 --quiet",
     "typecheck": "tsc",
     "format": "prettier --write '**/*.{ts,tsx,js,jsx}'",

sandpack-react/src/Playground.stories.tsx

@@ -11,19 +11,23 @@ export const Basic: React.FC = () => {
   return (
     <div style={{ height: "400vh" }}>
       <Sandpack
-        customSetup={{
-          dependencies: {
-            "react-content-loader": "latest",
-            "radix-ui": "latest",
-            "styled-components": "latest",
-            "react-dom": "latest",
-            react: "latest",
-            "react-table": "latest",
-          },
-        }}
         options={{
-          bundlerURL: "https://ymxnqs-3000.csb.app",
+          showTabs: true,
+          closableTabs: true,
         }}
+        // customSetup={{
+        //   dependencies: {
+        //     "react-content-loader": "latest",
+        //     "radix-ui": "latest",
+        //     "styled-components": "latest",
+        //     "react-dom": "latest",
+        //     react: "latest",
+        //     "react-table": "latest",
+        //   },
+        // }}
+        // options={{
+        //   bundlerURL: "https://ymxnqs-3000.csb.app",
+        // }}
         template="react"
       />
     </div>

sandpack-react/src/components/CodeEditor/index.tsx

@@ -6,6 +6,7 @@ import { useActiveCode } from "../../hooks/useActiveCode";
 import { useSandpack } from "../../hooks/useSandpack";
 import type { CustomLanguage, SandpackInitMode } from "../../types";
 import { useClassNames } from "../../utils/classNames";
+import { useSandpackId } from "../../utils/useAsyncSandpackId";
 import { FileTabs } from "../FileTabs";
 import { RunButton } from "../common/RunButton";
 import { SandpackStack } from "../common/Stack";
@@ -94,11 +95,23 @@ export const SandpackCodeEditor = forwardRef<CodeMirrorRef, CodeEditorProps>(
       updateCode(newCode, shouldUpdatePreview);
     };
 
+    const activeFileUniqueId = useSandpackId();
+
     return (
       <SandpackStack className={classNames("editor", [className])} {...props}>
-        {shouldShowTabs && <FileTabs closableTabs={closableTabs} />}
+        {shouldShowTabs && (
+          <FileTabs
+            activeFileUniqueId={activeFileUniqueId}
+            closableTabs={closableTabs}
+          />
+        )}
 
-        <div className={classNames("code-editor", [editorClassName])}>
+        <div
+          aria-labelledby={`${activeFile}-${activeFileUniqueId}-tab`}
+          className={classNames("code-editor", [editorClassName])}
+          id={`${activeFile}-${activeFileUniqueId}-tab-panel`}
+          role="tabpanel"
+        >
           <CodeMirror
             key={activeFile}
             ref={ref}

sandpack-react/src/components/CodeEditor/styles.ts

@@ -27,6 +27,9 @@ export const editorClassName = css({
   [`.${placeholderClassName}`]: {
     padding: "$space$4 0",
   },
+  "&:focus-within": {
+    outline: "$colors$accent auto 1px",
+  },
 
   /**
    * For iOS: prevent browser zoom when clicking on sandbox.

sandpack-react/src/components/CodeEditor/utils.ts

@@ -37,7 +37,11 @@ export const getEditorTheme = (): Extension =>
       outline: "none",
     },
 
-    ".cm-activeLine": {
+    "& .cm-activeLine": {
+      backgroundColor: "transparent",
+    },
+
+    "&.cm-editor.cm-focused .cm-activeLine": {
       backgroundColor: `var(--${THEME_PREFIX}-colors-surface3)`,
       borderRadius: `var(--${THEME_PREFIX}-border-radius)`,
     },

sandpack-react/src/components/FileTabs/index.tsx

@@ -25,12 +25,28 @@ const tabsScrollableClassName = css({
   marginBottom: "-1px",
 });
 
+const tabContainer = css({
+  display: "flex",
+  alignItems: "center",
+  outline: "none",
+  position: "relative",
+  paddingRight: "20px",
+  margin: "1px 0",
+
+  "&:has(button:focus)": {
+    outline: "$colors$accent auto 1px",
+  },
+});
+
 const closeButtonClassName = css({
   padding: "0 $space$1 0 $space$1",
   borderRadius: "$border$radius",
   marginLeft: "$space$1",
   width: "$space$5",
   visibility: "hidden",
+  cursor: "pointer",
+  position: "absolute",
+  right: "0px",
 
   svg: {
     width: "$space$3",
@@ -46,15 +62,22 @@ export const tabButton = css({
   height: "$layout$headerHeight",
   whiteSpace: "nowrap",
 
-  "&:focus": { outline: "none" },
-  [`&:hover > .${closeButtonClassName}`]: { visibility: "unset" },
+  "&:focus": {
+    outline: "none",
+  },
+  [`&:hover ~ .${closeButtonClassName}`]: { visibility: "visible" },
 });
 
 export interface FileTabsProps {
   /**
    * This adds a close button next to each file with a unique trigger to close it.
    */
   closableTabs?: boolean;
+  /**
+   * unique id appended with active files. This is
+   * used in aria-controls value along the combination of activeFile
+   */
+  activeFileUniqueId: string;
 }
 
 /**
@@ -70,6 +93,7 @@ export const FileTabs = ({
   const classNames = useClassNames();
 
   const { activeFile, visibleFiles, setActiveFile } = sandpack;
+  const [hoveredIndex, setIsHoveredIndex] = React.useState<null | number>(null);
 
   const handleCloseFile = (ev: React.MouseEvent<HTMLDivElement>): void => {
     ev.stopPropagation();
@@ -111,6 +135,56 @@ export const FileTabs = ({
     }
   };
 
+  const onKeyDown = ({
+    e,
+    index,
+  }: {
+    e: React.KeyboardEvent<HTMLElement>;
+    index: number;
+  }) => {
+    const target = e.currentTarget as HTMLElement;
+
+    switch (e.key) {
+      case "ArrowLeft":
+        {
+          const leftSibling = target.previousElementSibling as HTMLElement;
+
+          if (leftSibling) {
+            leftSibling.querySelector("button")?.focus();
+            setActiveFile(visibleFiles[index - 1]);
+          }
+        }
+        break;
+      case "ArrowRight":
+        {
+          const rightSibling = target.nextElementSibling as HTMLElement;
+
+          if (rightSibling) {
+            rightSibling.querySelector("button")?.focus();
+            setActiveFile(visibleFiles[index + 1]);
+          }
+        }
+        break;
+      case "Home": {
+        const parent = target.parentElement as HTMLElement;
+
+        const firstChild = parent.firstElementChild as HTMLElement;
+        firstChild.querySelector("button")?.focus();
+        setActiveFile(visibleFiles[0]);
+        break;
+      }
+      case "End": {
+        const parent = target.parentElement as HTMLElement;
+        const lastChild = parent.lastElementChild as HTMLElement;
+        lastChild.querySelector("button")?.focus();
+        setActiveFile(visibleFiles[-1]);
+        break;
+      }
+      default:
+        break;
+    }
+  };
+
   return (
     <div
       className={classNames("tabs", [tabsClassName, className])}
@@ -124,27 +198,44 @@ export const FileTabs = ({
         ])}
         role="tablist"
       >
-        {visibleFiles.map((filePath) => (
-          <button
-            key={filePath}
-            aria-selected={filePath === activeFile}
-            className={classNames("tab-button", [buttonClassName, tabButton])}
-            data-active={filePath === activeFile}
-            onClick={(): void => setActiveFile(filePath)}
-            role="tab"
-            title={filePath}
-            type="button"
+        {visibleFiles.map((filePath, index) => (
+          <div
+            className={classNames("tab-container", [tabContainer])}
+            onKeyDown={(e) => onKeyDown({ e, index })}
+            onMouseEnter={() => setIsHoveredIndex(index)}
+            onMouseLeave={() => setIsHoveredIndex(null)}
           >
-            {getTriggerText(filePath)}
+            <button
+              key={filePath}
+              aria-controls={`${filePath}-${props.activeFileUniqueId}-tab-panel`}
+              aria-selected={filePath === activeFile}
+              className={classNames("tab-button", [buttonClassName, tabButton])}
+              data-active={filePath === activeFile}
+              id={`${filePath}-${props.activeFileUniqueId}-tab`}
+              onClick={(): void => setActiveFile(filePath)}
+              role="tab"
+              tabIndex={filePath === activeFile ? 0 : -1}
+              title={filePath}
+              type="button"
+            >
+              {getTriggerText(filePath)}
+            </button>
             {closableTabs && visibleFiles.length > 1 && (
               <span
                 className={classNames("close-button", [closeButtonClassName])}
                 onClick={handleCloseFile}
+                style={{
+                  visibility:
+                    filePath === activeFile || hoveredIndex === index
+                      ? "visible"
+                      : "hidden",
+                }}
+                tabIndex={filePath === activeFile ? 0 : -1}
               >
                 <CloseIcon />
               </span>
             )}
-          </button>
+          </div>
         ))}
       </div>
     </div>

sandpack-react/src/utils/useAsyncSandpackId.ts

@@ -3,6 +3,15 @@ import { useId as useReactId } from "react";
 
 import { generateRandomId } from "./stringUtils";
 
+export const useSandpackId = () => {
+  if (typeof useReactId === "function") {
+    /* eslint-disable-next-line */
+    return useReactId();
+  } else {
+    return generateRandomId();
+  }
+};
+
 /**
  * This is a hard constraint to make URLs shorter.
  * For example, this id will be used to mount SW in the iframe