Add missing buffer-header.js

components/buffer-header.js

@@ -0,0 +1,20 @@
+import { html, Component } from "/lib/index.js";
+
+export default function BufferHeader(props) {
+	var topic = null;
+	if (props.buffer.topic) {
+		topic = html`<span class="topic">${props.buffer.topic}</span>`;
+	}
+
+	function handlePartClick(event) {
+		event.preventDefault();
+		props.onClose();
+	}
+
+	return html`
+		${topic}
+		<span class="actions">
+			<a href="#" onClick=${handlePartClick}>Part</a>
+		</span>
+	`;
+}