Fixes to correct solution

6 years ago · 6eefb4b601
parent f7e015037e
commit 6eefb4b601
1 changed files with 2 additions and 1 deletions
--- a/store.mjs
+++ b/store.mjs
@ -66,6 +66,7 @@ export function derive(stores, fn) {
 	const single = !Array.isArray(stores);
 	if (single) stores = [stores];

+	const auto = fn.length < 2;
 	let value = {};

 	return readable(set => {
@ -77,7 +78,7 @@ export function derive(stores, fn) {
 		const sync = () => {
 			if (pending) return;
 			const result = fn(single ? values[0] : values, set);
-			if (value !== (value = result)) set(result);
+			if (auto && (value !== (value = result))) set(result);
 		}

 		const unsubscribers = stores.map((store, i) => store.subscribe(