[docs] Add TS versionn of WithWidth demo

Author: burtyish

docs/src/pages/customization/breakpoints/WithWidth.tsx

@@ -0,0 +1,25 @@
+import React from 'react';
+import withWidth from '@material-ui/core/withWidth';
+import Typography from '@material-ui/core/Typography';
+import { Breakpoint } from '@material-ui/core/styles/createBreakpoints';
+
+type TagName = 'em' | 'u' | 'del';
+
+const components: Partial<Record<Breakpoint, TagName>> = {
+  sm: 'em',
+  md: 'u',
+  lg: 'del',
+};
+
+function WithWidth(props: { width: Breakpoint }) {
+  const { width } = props;
+  const Component = components[width] || 'span';
+
+  return (
+    <Typography variant="subtitle1">
+      <Component>{`Current width: ${width}`}</Component>
+    </Typography>
+  );
+}
+
+export default withWidth()(WithWidth);