chore: simplify flushing (#15348)

* this appears to be unnecessary

* DRY out

* this doesnt appear to do anything useful

* simplify

* remove unused if block

* simplify, make non-recursive

* unused

* DRY

* simplify

* tidy up

* simplify

* changeset

* unused

* Revert "changeset"

This reverts commit 946e00d.

* make flush_sync non-recursive

* fix flushSync types

* fix

* unused

* simplify

* tidy up

* tidy up

* present unnecessary microtasks, avoid flushing if no function provided

* simplify

Author: Rich-Harris

.changeset/violet-camels-heal.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: update types and inline docs for flushSync

benchmarking/benchmarks/reactivity/kairo/kairo_avoidable.js

@@ -20,12 +20,12 @@ function setup() {
 	return {
 		destroy,
 		run() {
-			$.flush_sync(() => {
+			$.flush(() => {
 				$.set(head, 1);
 			});
 			assert($.get(computed5) === 6);
 			for (let i = 0; i < 1000; i++) {
-				$.flush_sync(() => {
+				$.flush(() => {
 					$.set(head, i);
 				});
 				assert($.get(computed5) === 6);

benchmarking/benchmarks/reactivity/kairo/kairo_broad.js

@@ -25,12 +25,12 @@ function setup() {
 	return {
 		destroy,
 		run() {
-			$.flush_sync(() => {
+			$.flush(() => {
 				$.set(head, 1);
 			});
 			counter = 0;
 			for (let i = 0; i < 50; i++) {
-				$.flush_sync(() => {
+				$.flush(() => {
 					$.set(head, i);
 				});
 				assert($.get(last) === i + 50);

benchmarking/benchmarks/reactivity/kairo/kairo_deep.js

@@ -25,12 +25,12 @@ function setup() {
 	return {
 		destroy,
 		run() {
-			$.flush_sync(() => {
+			$.flush(() => {
 				$.set(head, 1);
 			});
 			counter = 0;
 			for (let i = 0; i < iter; i++) {
-				$.flush_sync(() => {
+				$.flush(() => {
 					$.set(head, i);
 				});
 				assert($.get(current) === len + i);

benchmarking/benchmarks/reactivity/kairo/kairo_diamond.js

@@ -28,13 +28,13 @@ function setup() {
 	return {
 		destroy,
 		run() {
-			$.flush_sync(() => {
+			$.flush(() => {
 				$.set(head, 1);
 			});
 			assert($.get(sum) === 2 * width);
 			counter = 0;
 			for (let i = 0; i < 500; i++) {
-				$.flush_sync(() => {
+				$.flush(() => {
 					$.set(head, i);
 				});
 				assert($.get(sum) === (i + 1) * width);

benchmarking/benchmarks/reactivity/kairo/kairo_mux.js

@@ -22,13 +22,13 @@ function setup() {
 		destroy,
 		run() {
 			for (let i = 0; i < 10; i++) {
-				$.flush_sync(() => {
+				$.flush(() => {
 					$.set(heads[i], i);
 				});
 				assert($.get(splited[i]) === i + 1);
 			}
 			for (let i = 0; i < 10; i++) {
-				$.flush_sync(() => {
+				$.flush(() => {
 					$.set(heads[i], i * 2);
 				});
 				assert($.get(splited[i]) === i * 2 + 1);

benchmarking/benchmarks/reactivity/kairo/kairo_repeated.js

@@ -25,13 +25,13 @@ function setup() {
 	return {
 		destroy,
 		run() {
-			$.flush_sync(() => {
+			$.flush(() => {
 				$.set(head, 1);
 			});
 			assert($.get(current) === size);
 			counter = 0;
 			for (let i = 0; i < 100; i++) {
-				$.flush_sync(() => {
+				$.flush(() => {
 					$.set(head, i);
 				});
 				assert($.get(current) === i * size);

benchmarking/benchmarks/reactivity/kairo/kairo_triangle.js

@@ -38,13 +38,13 @@ function setup() {
 		destroy,
 		run() {
 			const constant = count(width);
-			$.flush_sync(() => {
+			$.flush(() => {
 				$.set(head, 1);
 			});
 			assert($.get(sum) === constant);
 			counter = 0;
 			for (let i = 0; i < 100; i++) {
-				$.flush_sync(() => {
+				$.flush(() => {
 					$.set(head, i);
 				});
 				assert($.get(sum) === constant - width + i * width);

benchmarking/benchmarks/reactivity/kairo/kairo_unstable.js

@@ -25,13 +25,13 @@ function setup() {
 	return {
 		destroy,
 		run() {
-			$.flush_sync(() => {
+			$.flush(() => {
 				$.set(head, 1);
 			});
 			assert($.get(current) === 40);
 			counter = 0;
 			for (let i = 0; i < 100; i++) {
-				$.flush_sync(() => {
+				$.flush(() => {
 					$.set(head, i);
 				});
 			}

benchmarking/benchmarks/reactivity/mol_bench.js

@@ -51,11 +51,11 @@ function setup() {
 		 */
 		run(i) {
 			res.length = 0;
-			$.flush_sync(() => {
+			$.flush(() => {
 				$.set(B, 1);
 				$.set(A, 1 + i * 2);
 			});
-			$.flush_sync(() => {
+			$.flush(() => {
 				$.set(A, 2 + i * 2);
 				$.set(B, 2);
 			});