ssb: Alt+up/down to cycle through channels.

apps/ssb.json

@@ -1,5 +1,5 @@
 {
 	"type": "tildefriends-app",
 	"emoji": "🐌",
-	"previous": "&hWgKPOx3M3T7BufeywObcOCHvsdRfVAoZ9LErkPhJPE=.sha256"
+	"previous": "&tkrwd7UkPaWUk9189g3D08N44EjT0AJOlDLw6oMfbpY=.sha256"
 }

apps/ssb/tf-app.js

@@ -97,6 +97,36 @@ class TfElement extends LitElement {
 		this.channels = Object.keys(channel_map).sort();
 	}
 
+	connectedCallback() {
+		super.connectedCallback();
+		this._keydown = this.keydown.bind(this);
+		window.addEventListener('keydown', this._keydown);
+	}
+
+	disconnectedCallback() {
+		super.disconnectedCallback();
+		window.removeEventListener('keydown', this._keydown);
+	}
+
+	keydown(event) {
+		if (event.altKey && event.key == 'ArrowUp') {
+			this.next_channel(1);
+			event.preventDefault();
+		} else if (event.altKey && event.key == 'ArrowDown') {
+			this.next_channel(-1);
+			event.preventDefault();
+		}
+	}
+
+	next_channel(delta) {
+		let channel_names = ['', '@'].concat(this.channels);
+		let index = channel_names.indexOf(this.hash.substring(1));
+		if (index != -1) {
+			index += delta;
+			this.set_hash('#' + encodeURIComponent(channel_names[(index + channel_names.length) % channel_names.length]));
+		}
+	}
+
 	set_hash(hash) {
 		this.hash = decodeURIComponent(hash || '#');
 		if (this.hash.startsWith('#q=')) {