support automatic reset of expanded arrays/objects when DefaultExpand setting changes

Author: dmackdev

src/default_expand.rs

@@ -2,7 +2,7 @@ use std::collections::HashSet;
 
 use egui::Id;
 
-#[derive(Debug, Clone, Copy, Default)]
+#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Hash)]
 /// Configuration for how a [`JsonTree`](crate::JsonTree) should expand arrays and objects by default.
 pub enum DefaultExpand<'a> {
     /// Expand all arrays and objects.
@@ -25,7 +25,7 @@ pub enum DefaultExpand<'a> {
     SearchResultsOrAll(&'a str),
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug)]
 /// Internal representation for the [`DefaultExpand`] setting.
 pub(crate) enum InnerDefaultExpand {
     All,

src/node.rs

@@ -85,9 +85,30 @@ impl<'a, 'b, T: ToJsonTreeValue> JsonTreeNode<'a, 'b, T> {
             node.show_impl(ui, &mut vec![], &mut reset_path_ids, &mut renderer);
         });
 
-        JsonTreeResponse {
+        let should_reset_expanded = if tree.config.auto_reset_expanded {
+            let default_expand_hash_id = ResetExpandedHashId(egui::util::hash(default_expand));
+            let default_expand_changed = ui.ctx().data_mut(|d| {
+                let default_expand_changed =
+                    d.get_temp::<ResetExpandedHashId>(tree.id) != Some(default_expand_hash_id);
+                if default_expand_changed {
+                    d.insert_temp(tree.id, default_expand_hash_id);
+                }
+                default_expand_changed
+            });
+            default_expand_changed
+        } else {
+            false
+        };
+
+        let response = JsonTreeResponse {
             collapsing_state_ids: reset_path_ids,
+        };
+
+        if should_reset_expanded {
+            response.reset_expanded(ui);
         }
+
+        response
     }
 
     fn show_impl(
@@ -458,3 +479,8 @@ struct JsonTreeNodeConfig {
     style: JsonTreeStyle,
     search_term: Option<SearchTerm>,
 }
+
+/// Stored in `egui`'s `IdTypeMap` to represent a hashed value to indicate whether to reset expanded arrays/objects when this changes for a particular tree Id.
+/// Avoids potential conflicts in case a `u64` happened to be stored against the same tree Id.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+struct ResetExpandedHashId(u64);

src/tree.rs

@@ -10,6 +10,7 @@ use std::hash::Hash;
 pub(crate) struct JsonTreeConfig<'a, T: ToJsonTreeValue> {
     pub(crate) style: Option<JsonTreeStyle>,
     pub(crate) default_expand: Option<DefaultExpand<'a>>,
+    pub(crate) auto_reset_expanded: bool,
     pub(crate) renderer: JsonTreeRenderer<'a, T>,
 }
 
@@ -18,6 +19,7 @@ impl<T: ToJsonTreeValue> Default for JsonTreeConfig<'_, T> {
         Self {
             style: Default::default(),
             default_expand: Default::default(),
+            auto_reset_expanded: false,
             renderer: Default::default(),
         }
     }
@@ -54,6 +56,12 @@ impl<'a, T: ToJsonTreeValue> JsonTree<'a, T> {
         self
     }
 
+    /// Automatically reset expanded arrays/objects to respect the [`DefaultExpand`] setting when it changes.
+    pub fn auto_reset_expanded(mut self, auto_reset_expanded: bool) -> Self {
+        self.config.auto_reset_expanded = auto_reset_expanded;
+        self
+    }
+
     /// A convenience method for conditionally registering a custom rendering hook.
     /// See [`JsonTree::on_render`].
     pub fn on_render_if(