From c7895db46102bbdc840a57900b2630fe1d8c5c81 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Tue, 20 Feb 2024 18:10:59 -0500
Subject: [PATCH] move source code

---
 .../src/internal/client/dom/blocks/each.js    |  5 +-
 .../src/internal/client/dom/blocks/key.js     |  4 +-
 packages/svelte/src/internal/client/proxy.js  |  3 +-
 .../internal/client/reactivity/equality.js    | 30 ++++++
 .../src/internal/client/reactivity/sources.js | 75 ++++++++++++++
 .../svelte/src/internal/client/runtime.js     | 99 +------------------
 .../svelte/src/internal/client/validate.js    |  3 +-
 packages/svelte/src/internal/index.js         |  5 +-
 packages/svelte/tests/signals/test.ts         | 27 ++---
 9 files changed, 129 insertions(+), 122 deletions(-)
 create mode 100644 packages/svelte/src/internal/client/reactivity/equality.js
 create mode 100644 packages/svelte/src/internal/client/reactivity/sources.js

diff --git a/packages/svelte/src/internal/client/dom/blocks/each.js b/packages/svelte/src/internal/client/dom/blocks/each.js
index b068869c59..ef3c9c9ed8 100644
--- a/packages/svelte/src/internal/client/dom/blocks/each.js
+++ b/packages/svelte/src/internal/client/dom/blocks/each.js
@@ -21,12 +21,11 @@ import {
 	current_block,
 	destroy_signal,
 	execute_effect,
-	mutable_source,
 	push_destroy_fn,
-	set_signal_value,
-	source
+	set_signal_value
 } from '../../runtime.js';
 import { render_effect } from '../../reactivity/effects.js';
+import { source, mutable_source } from '../../reactivity/sources.js';
 import { trigger_transitions } from '../../transitions.js';
 import { is_array } from '../../utils.js';
 
diff --git a/packages/svelte/src/internal/client/dom/blocks/key.js b/packages/svelte/src/internal/client/dom/blocks/key.js
index ed1541d327..fbe716a9a2 100644
--- a/packages/svelte/src/internal/client/dom/blocks/key.js
+++ b/packages/svelte/src/internal/client/dom/blocks/key.js
@@ -6,11 +6,11 @@ import {
 	current_block,
 	destroy_signal,
 	execute_effect,
-	push_destroy_fn,
-	safe_not_equal
+	push_destroy_fn
 } from '../../runtime.js';
 import { render_effect } from '../../reactivity/effects.js';
 import { trigger_transitions } from '../../transitions.js';
+import { safe_not_equal } from '../../reactivity/equality.js';
 
 /** @returns {import('../../types.js').KeyBlock} */
 function create_key_block() {
diff --git a/packages/svelte/src/internal/client/proxy.js b/packages/svelte/src/internal/client/proxy.js
index 9a8cf2cb63..60b4165d75 100644
--- a/packages/svelte/src/internal/client/proxy.js
+++ b/packages/svelte/src/internal/client/proxy.js
@@ -3,10 +3,8 @@ import {
 	get,
 	set,
 	update,
-	source,
 	updating_derived,
 	UNINITIALIZED,
-	mutable_source,
 	batch_inspect,
 	current_component_context
 } from './runtime.js';
@@ -22,6 +20,7 @@ import {
 	object_prototype
 } from './utils.js';
 import { add_owner, check_ownership, strip_owner } from './dev/ownership.js';
+import { mutable_source, source } from './reactivity/sources.js';
 
 export const STATE_SYMBOL = Symbol('$state');
 
diff --git a/packages/svelte/src/internal/client/reactivity/equality.js b/packages/svelte/src/internal/client/reactivity/equality.js
new file mode 100644
index 0000000000..34673b2dda
--- /dev/null
+++ b/packages/svelte/src/internal/client/reactivity/equality.js
@@ -0,0 +1,30 @@
+/**
+ * @param {unknown} a
+ * @param {unknown} b
+ * @returns {boolean}
+ */
+export function default_equals(a, b) {
+	return a === b;
+}
+
+/**
+ * @param {unknown} a
+ * @param {unknown} b
+ * @returns {boolean}
+ */
+export function safe_not_equal(a, b) {
+	// eslint-disable-next-line eqeqeq
+	return a != a
+		? // eslint-disable-next-line eqeqeq
+			b == b
+		: a !== b || (a !== null && typeof a === 'object') || typeof a === 'function';
+}
+
+/**
+ * @param {unknown} a
+ * @param {unknown} b
+ * @returns {boolean}
+ */
+export function safe_equal(a, b) {
+	return !safe_not_equal(a, b);
+}
diff --git a/packages/svelte/src/internal/client/reactivity/sources.js b/packages/svelte/src/internal/client/reactivity/sources.js
new file mode 100644
index 0000000000..a889e9c31e
--- /dev/null
+++ b/packages/svelte/src/internal/client/reactivity/sources.js
@@ -0,0 +1,75 @@
+/**
+ * @template V
+ * @param {V} initial_value
+ * @returns {import('../types.js').SourceSignal<V>}
+ */
+
+import { DEV } from 'esm-env';
+import { CLEAN, SOURCE, current_component_context } from '../runtime.js';
+import { default_equals, safe_equal } from './equality.js';
+
+/**
+ * @template V
+ * @param {V} initial_value
+ * @returns {import('../types.js').SourceSignal<V>}
+ */
+/*#__NO_SIDE_EFFECTS__*/
+export function source(initial_value) {
+	return create_source_signal(SOURCE | CLEAN, initial_value);
+}
+
+/**
+ * @template V
+ * @param {V} initial_value
+ * @returns {import('../types.js').SourceSignal<V>}
+ */
+/*#__NO_SIDE_EFFECTS__*/
+export function mutable_source(initial_value) {
+	const s = source(initial_value);
+	s.e = safe_equal;
+
+	// bind the signal to the component context, in case we need to
+	// track updates to trigger beforeUpdate/afterUpdate callbacks
+	if (current_component_context) {
+		(current_component_context.d ??= []).push(s);
+	}
+
+	return s;
+}
+
+/**
+ * @template V
+ * @param {import('../types.js').SignalFlags} flags
+ * @param {V} value
+ * @returns {import('../types.js').SourceSignal<V> | import('../types.js').SourceSignal<V> & import('../types.js').SourceSignalDebug}
+ */
+function create_source_signal(flags, value) {
+	if (DEV) {
+		return {
+			// consumers
+			c: null,
+			// equals
+			e: default_equals,
+			// flags
+			f: flags,
+			// value
+			v: value,
+			// write version
+			w: 0,
+			// this is for DEV only
+			inspect: new Set()
+		};
+	}
+	return {
+		// consumers
+		c: null,
+		// equals
+		e: default_equals,
+		// flags
+		f: flags,
+		// value
+		v: value,
+		// write version
+		w: 0
+	};
+}
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 87bc7f4291..960b25abce 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -20,6 +20,8 @@ import {
 import { STATE_SYMBOL, unstate } from './proxy.js';
 import { EACH_BLOCK, IF_BLOCK } from './block.js';
 import { pre_effect, user_effect } from './reactivity/effects.js';
+import { mutable_source, source } from './reactivity/sources.js';
+import { default_equals, safe_equal, safe_not_equal } from './reactivity/equality.js';
 
 export const SOURCE = 1;
 export const DERIVED = 1 << 1;
@@ -145,52 +147,6 @@ export function batch_inspect(target, prop, receiver) {
 	};
 }
 
-/**
- * @param {unknown} a
- * @param {unknown} b
- * @returns {boolean}
- */
-export function default_equals(a, b) {
-	return a === b;
-}
-
-/**
- * @template V
- * @param {import('./types.js').SignalFlags} flags
- * @param {V} value
- * @returns {import('./types.js').SourceSignal<V> | import('./types.js').SourceSignal<V> & import('./types.js').SourceSignalDebug}
- */
-function create_source_signal(flags, value) {
-	if (DEV) {
-		return {
-			// consumers
-			c: null,
-			// equals
-			e: default_equals,
-			// flags
-			f: flags,
-			// value
-			v: value,
-			// write version
-			w: 0,
-			// this is for DEV only
-			inspect: new Set()
-		};
-	}
-	return {
-		// consumers
-		c: null,
-		// equals
-		e: default_equals,
-		// flags
-		f: flags,
-		// value
-		v: value,
-		// write version
-		w: 0
-	};
-}
-
 /**
  * @template V
  * @param {import('./types.js').SignalFlags} flags
@@ -1328,35 +1284,6 @@ export function derived_safe_equal(init) {
 	return signal;
 }
 
-/**
- * @template V
- * @param {V} initial_value
- * @returns {import('./types.js').SourceSignal<V>}
- */
-/*#__NO_SIDE_EFFECTS__*/
-export function source(initial_value) {
-	return create_source_signal(SOURCE | CLEAN, initial_value);
-}
-
-/**
- * @template V
- * @param {V} initial_value
- * @returns {import('./types.js').SourceSignal<V>}
- */
-/*#__NO_SIDE_EFFECTS__*/
-export function mutable_source(initial_value) {
-	const s = source(initial_value);
-	s.e = safe_equal;
-
-	// bind the signal to the component context, in case we need to
-	// track updates to trigger beforeUpdate/afterUpdate callbacks
-	if (current_component_context) {
-		(current_component_context.d ??= []).push(s);
-	}
-
-	return s;
-}
-
 /**
  * Use `untrack` to prevent something from being treated as an `$effect`/`$derived` dependency.
  *
@@ -1542,28 +1469,6 @@ export function prop(props, key, flags, initial) {
 	};
 }
 
-/**
- * @param {unknown} a
- * @param {unknown} b
- * @returns {boolean}
- */
-export function safe_not_equal(a, b) {
-	// eslint-disable-next-line eqeqeq
-	return a != a
-		? // eslint-disable-next-line eqeqeq
-			b == b
-		: a !== b || (a !== null && typeof a === 'object') || typeof a === 'function';
-}
-
-/**
- * @param {unknown} a
- * @param {unknown} b
- * @returns {boolean}
- */
-export function safe_equal(a, b) {
-	return !safe_not_equal(a, b);
-}
-
 /** @returns {Map<unknown, unknown>} */
 export function get_or_init_context_map() {
 	const component_context = current_component_context;
diff --git a/packages/svelte/src/internal/client/validate.js b/packages/svelte/src/internal/client/validate.js
index c6f590a420..83124697a8 100644
--- a/packages/svelte/src/internal/client/validate.js
+++ b/packages/svelte/src/internal/client/validate.js
@@ -1,5 +1,4 @@
-import { EACH_INDEX_REACTIVE } from '../../constants.js';
-import { source, untrack } from './runtime.js';
+import { untrack } from './runtime.js';
 import { is_array } from './utils.js';
 
 /** regex of all html void element names */
diff --git a/packages/svelte/src/internal/index.js b/packages/svelte/src/internal/index.js
index aa38e22d35..c8262e2cdd 100644
--- a/packages/svelte/src/internal/index.js
+++ b/packages/svelte/src/internal/index.js
@@ -4,14 +4,11 @@ export {
 	set,
 	set_sync,
 	invalidate_inner_signals,
-	source,
-	mutable_source,
 	derived,
 	derived_safe_equal,
 	prop,
 	flushSync,
 	bubble_event,
-	safe_equal,
 	tick,
 	untrack,
 	update,
@@ -41,6 +38,8 @@ export { if_block as if } from './client/dom/blocks/if.js';
 export { key_block as key } from './client/dom/blocks/key.js';
 export * from './client/dom/blocks/each.js';
 export * from './client/reactivity/effects.js';
+export * from './client/reactivity/sources.js';
+export * from './client/reactivity/equality.js';
 export * from './client/render.js';
 export * from './client/validate.js';
 export { raf } from './client/timing.js';
diff --git a/packages/svelte/tests/signals/test.ts b/packages/svelte/tests/signals/test.ts
index 2713ae9ba1..2628a67fa6 100644
--- a/packages/svelte/tests/signals/test.ts
+++ b/packages/svelte/tests/signals/test.ts
@@ -1,6 +1,7 @@
 import { describe, assert, it } from 'vitest';
 import * as $ from '../../src/internal/client/runtime';
 import { effect, render_effect, user_effect } from '../../src/internal/client/reactivity/effects';
+import { source } from '../../src/internal/client/reactivity/sources';
 import type { ComputationSignal } from '../../src/internal/client/types';
 
 /**
@@ -37,7 +38,7 @@ describe('signals', () => {
 	test('effect with state and derived in it', () => {
 		const log: string[] = [];
 
-		let count = $.source(0);
+		let count = source(0);
 		let double = $.derived(() => $.get(count) * 2);
 		effect(() => {
 			log.push(`${$.get(count)}:${$.get(double)}`);
@@ -54,7 +55,7 @@ describe('signals', () => {
 	test('multiple effects with state and derived in it#1', () => {
 		const log: string[] = [];
 
-		let count = $.source(0);
+		let count = source(0);
 		let double = $.derived(() => $.get(count) * 2);
 
 		effect(() => {
@@ -75,7 +76,7 @@ describe('signals', () => {
 	test('multiple effects with state and derived in it#2', () => {
 		const log: string[] = [];
 
-		let count = $.source(0);
+		let count = source(0);
 		let double = $.derived(() => $.get(count) * 2);
 
 		effect(() => {
@@ -96,7 +97,7 @@ describe('signals', () => {
 	test('derived from state', () => {
 		const log: number[] = [];
 
-		let count = $.source(0);
+		let count = source(0);
 		let double = $.derived(() => $.get(count) * 2);
 
 		effect(() => {
@@ -114,7 +115,7 @@ describe('signals', () => {
 	test('derived from derived', () => {
 		const log: number[] = [];
 
-		let count = $.source(0);
+		let count = source(0);
 		let double = $.derived(() => $.get(count) * 2);
 		let quadruple = $.derived(() => $.get(double) * 2);
 
@@ -137,8 +138,8 @@ describe('signals', () => {
 		const fib = (n: number): number => (n < 2 ? 1 : fib(n - 1) + fib(n - 2));
 		const hard = (n: number, l: string) => n + fib(16);
 
-		const A = $.source(0);
-		const B = $.source(0);
+		const A = source(0);
+		const B = source(0);
 		const C = $.derived(() => ($.get(A) % 2) + ($.get(B) % 2));
 		const D = $.derived(() => numbers.map((i) => i + ($.get(A) % 2) - ($.get(B) % 2)));
 		const E = $.derived(() => hard($.get(C) + $.get(A) + $.get(D)[0]!, 'E'));
@@ -177,7 +178,7 @@ describe('signals', () => {
 	test('effects correctly handle unowned derived values that do not change', () => {
 		const log: number[] = [];
 
-		let count = $.source(0);
+		let count = source(0);
 		const read = () => {
 			const x = $.derived(() => ({ count: $.get(count) }));
 			return $.get(x);
@@ -205,8 +206,8 @@ describe('signals', () => {
 		return () => {
 			const nested: ComputationSignal<string>[] = [];
 
-			const a = $.source(0);
-			const b = $.source(0);
+			const a = source(0);
+			const b = source(0);
 			const c = $.derived(() => {
 				const a_2 = $.derived(() => $.get(a) + '!');
 				const b_2 = $.derived(() => $.get(b) + '?');
@@ -234,7 +235,7 @@ describe('signals', () => {
 	});
 
 	// outside of test function so that they are unowned signals
-	let count = $.source(0);
+	let count = source(0);
 	let calc = $.derived(() => {
 		if ($.get(count) >= 2) {
 			return 'limit';
@@ -285,7 +286,7 @@ describe('signals', () => {
 		};
 	});
 
-	let some_state = $.source({});
+	let some_state = source({});
 	let some_deps = $.derived(() => {
 		return [$.get(some_state)];
 	});
@@ -310,7 +311,7 @@ describe('signals', () => {
 	test('schedules rerun when writing to signal before reading it', (runes) => {
 		if (!runes) return () => {};
 
-		const value = $.source({ count: 0 });
+		const value = source({ count: 0 });
 		user_effect(() => {
 			$.set(value, { count: 0 });
 			$.get(value);