strip wrapper divs, fix hideHeader

docs/src/modules/components/Demo.js

@@ -267,7 +267,8 @@ function Demo(props) {
   const match = useMediaQuery(theme => theme.breakpoints.up('sm'));
 
   const jsx = getJsxPreview(demoData.raw || '', demoOptions);
-  const showPreview = jsx !== demoData.raw && jsx.split(/\n/).length <= 20;
+  const showPreview =
+    !demoOptions.hideHeader && jsx !== demoData.raw && jsx.split(/\n/).length <= 20;
 
   let showCodeLabel;
   if (codeOpen) {

docs/src/modules/utils/getJsxPreview.js

@@ -1,28 +1,31 @@
 // docs/pages/components/material-icons.js doesn't provide the source
 export default function getJsxPreview(code, demoOptions) {
-/* regex matches the content of the return statement in the default export:
- *
- * `export default.*`
- * `\n  return (\n` or `\n  return `
- *
- *  everything (not greedy), until:
- *
- * `  );\n}` or `;\n}`
- */
-let jsx = code.match(
-  /export default .*(\n {2}return \(\n|\n {2}return )(.*?)(\n {2}\);\n}|;\n})/s,
-);
-/* Just the match, otherwise the full source if no match or disabled,
+  /* The regex matches the content of the return statement in the default export,
+   * stripping any wrapper divs:
+   *
+   * `export default.*`
+   * `\n  return (\n` or `\n  return `
+   * `    <div.*>\n` (optional)
+   * `      <div.*>\n` (optional)
+   *  everything until:
+   * `\n    </div>` (optional)
+   * `\n  </div>` (optional)
+   * `  );\n}` or `;\n}`
+   */
+  let jsx = code.match(
+    /export default .*(?:\n {2}return \(\n|\n {2}return )(?: {4}<div.*?>\n)?(?: {6}<div.*?>\n)?(.*?)(\n {6}<\/div>)?(\n {4}<\/div>)?(\n {2}\);\n}|;\n})/s,
+  );
+  /* Just the match, otherwise the full source if no match or disabled,
 so as not to break the Collapse transition. */
-jsx = jsx && demoOptions.defaultCodeOpen !== false ? jsx[2] : code;
+  jsx = jsx && demoOptions.defaultCodeOpen !== false ? jsx[1] : code;
 
-// Remove leading spaces from each line
-return jsx.split(/\n/).reduce(
-  (acc, line) =>
-    `${acc}${line.slice(
-      // Number of leading spaces on the first line
-      jsx.match(/^ */)[0].length,
-    )}\n`,
-  '',
-);
+  // Remove leading spaces from each line
+  return jsx.split(/\n/).reduce(
+    (acc, line) =>
+      `${acc}${line.slice(
+        // Number of leading spaces on the first line
+        jsx.match(/^ */)[0].length,
+      )}\n`,
+    '',
+  );
 }