feat: implement TreeState select first/last

examples/example.rs

@@ -91,11 +91,13 @@ fn run_app<B: Backend>(terminal: &mut Terminal<B>, mut app: App) -> io::Result<(
         if let Event::Key(key) = event::read()? {
             match key.code {
                 KeyCode::Char('q') => return Ok(()),
+                KeyCode::Char('\n' | ' ') => app.tree.toggle(),
                 KeyCode::Left => app.tree.left(),
                 KeyCode::Right => app.tree.right(),
-                KeyCode::Char('\n') => app.tree.toggle(),
                 KeyCode::Down => app.tree.down(),
                 KeyCode::Up => app.tree.up(),
+                KeyCode::Home => app.tree.first(),
+                KeyCode::End => app.tree.last(),
                 _ => {}
             }
         }

examples/util/mod.rs

@@ -21,6 +21,14 @@ impl<'a> StatefulTree<'a> {
         }
     }
 
+    pub fn first(&mut self) {
+        self.state.select_first();
+    }
+
+    pub fn last(&mut self) {
+        self.state.select_last(&self.items);
+    }
+
     pub fn down(&mut self) {
         self.state.key_down(&self.items);
     }

src/lib.rs

@@ -86,6 +86,21 @@ impl TreeState {
         self.opened.clear();
     }
 
+    /// Select the first node.
+    pub fn select_first(&mut self) {
+        self.select(vec![0]);
+    }
+
+    /// Select the last node.
+    pub fn select_last(&mut self, items: &[TreeItem]) {
+        let visible = flatten(&self.get_all_opened(), items);
+        let new_identifier = visible
+            .last()
+            .map(|o| o.identifier.clone())
+            .unwrap_or_default();
+        self.select(new_identifier);
+    }
+
     /// Handles the up arrow key.
     /// Moves up in the current depth or to its parent.
     pub fn key_up(&mut self, items: &[TreeItem]) {