duplicates are rare and harmless

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

@@ -179,19 +179,13 @@ export class Batch {
 
 						for (const e of this.#render_effects) {
 							set_signal_status(e, CLEAN);
-							// TODO use sets instead of arrays
-							if (!batch.#render_effects.includes(e)) {
 							batch.#render_effects.push(e);
 						}
-						}
 
 						for (const e of this.#effects) {
 							set_signal_status(e, CLEAN);
-							// TODO use sets instead of arrays
-							if (!batch.#effects.includes(e)) {
 							batch.#effects.push(e);
 						}
-						}
 
 						for (const e of this.skipped_effects) {
 							batch.skipped_effects.add(e);