feat: support markdown

ui/components/Markdown/renderer/emphasis.tsx

@@ -0,0 +1,35 @@
+import { css, cx } from "@emotion/css";
+import type { Emphasis, Node } from "@yozora/ast";
+import React from "react";
+import { astClasses } from "../context";
+import { NodesRenderer } from "../NodesRenderer";
+
+/**
+ * Render `emphasis`.
+ *
+ * @see https://www.npmjs.com/package/@yozora/ast#emphasis
+ * @see https://www.npmjs.com/package/@yozora/tokenizer-emphasis
+ */
+export class EmphasisRenderer extends React.Component<Emphasis> {
+  public override shouldComponentUpdate(nextProps: Readonly<Emphasis>): boolean {
+    const props = this.props;
+    return props.children !== nextProps.children;
+  }
+
+  public override render(): React.ReactElement {
+    const childNodes: Node[] = this.props.children;
+    return (
+      <em className={cls}>
+        <NodesRenderer nodes={childNodes} />
+      </em>
+    );
+  }
+}
+
+const cls = cx(
+  astClasses.emphasis,
+  css({
+    fontStyle: "italic",
+    margin: "0 6px 0 2px",
+  }),
+);