WIP

packages/svelte/src/internal/client/reactivity/sources.js

@@ -44,6 +44,9 @@ export function set_inspect_effects(v) {
 	inspect_effects = v;
 }
 
+/** @type {Set<Source>} */
+export const changeset = new Set();
+
 /**
  * @template V
  * @param {V} v
@@ -181,6 +184,10 @@ export function internal_set(source, value) {
 			}
 		}
 
+		if (!changeset.has(source)) {
+			changeset.add(source);
+		}
+
 		mark_reactions(source, DIRTY);
 
 		// It's possible that the current reaction might not have up-to-date dependencies

packages/svelte/src/internal/client/runtime.js

@@ -31,7 +31,7 @@ import {
 	flush_boundary_micro_tasks,
 	flush_post_micro_tasks
 } from './dom/task.js';
-import { internal_set } from './reactivity/sources.js';
+import { changeset, internal_set } from './reactivity/sources.js';
 import {
 	destroy_derived_effects,
 	from_async_derived,
@@ -705,6 +705,7 @@ function flush_queued_root_effects(root_effects) {
 		}
 	} finally {
 		is_flushing_effect = previously_flushing_effect;
+		changeset.clear();
 	}
 }
 
@@ -825,6 +826,8 @@ function process_effects(effect, collected_effects, boundary) {
 			} else if ((flags & BOUNDARY_EFFECT) !== 0) {
 				var b = /** @type {Boundary} */ (current_effect.b);
 
+				console.log([...changeset].map((s) => s.v));
+
 				process_effects(current_effect, collected_effects, b);
 
 				if (!b.suspended) {