feat: added the prefer-svelte-reactivity rule

.changeset/rich-colts-nail.md

@@ -0,0 +1,5 @@
+---
+'eslint-plugin-svelte': minor
+---
+
+feat: added the `prefer-svelte-reactivity` rule

README.md

@@ -272,6 +272,7 @@ These rules relate to possible syntax or logic errors in Svelte code:
 | [svelte/no-shorthand-style-property-overrides](https://sveltejs.github.io/eslint-plugin-svelte/rules/no-shorthand-style-property-overrides/) | disallow shorthand style properties that override related longhand properties | :star: |
 | [svelte/no-store-async](https://sveltejs.github.io/eslint-plugin-svelte/rules/no-store-async/) | disallow using async/await inside svelte stores because it causes issues with the auto-unsubscribing features | :star: |
 | [svelte/no-unknown-style-directive-property](https://sveltejs.github.io/eslint-plugin-svelte/rules/no-unknown-style-directive-property/) | disallow unknown `style:property` | :star: |
+| [svelte/prefer-svelte-reactivity](https://sveltejs.github.io/eslint-plugin-svelte/rules/prefer-svelte-reactivity/) | disallow using built-in classes where a reactive alternative is provided by svelte/reactivity | :star: |
 | [svelte/require-store-callbacks-use-set-param](https://sveltejs.github.io/eslint-plugin-svelte/rules/require-store-callbacks-use-set-param/) | store callbacks must use `set` param |  |
 | [svelte/require-store-reactive-access](https://sveltejs.github.io/eslint-plugin-svelte/rules/require-store-reactive-access/) | disallow to use of the store itself as an operand. Need to use $ prefix or get function. | :star::wrench: |
 | [svelte/valid-compile](https://sveltejs.github.io/eslint-plugin-svelte/rules/valid-compile/) | disallow warnings when compiling. |  |

docs/rules.md

@@ -29,6 +29,7 @@ These rules relate to possible syntax or logic errors in Svelte code:
 | [svelte/no-shorthand-style-property-overrides](./rules/no-shorthand-style-property-overrides.md) | disallow shorthand style properties that override related longhand properties                                                          | :star:         |
 | [svelte/no-store-async](./rules/no-store-async.md)                                               | disallow using async/await inside svelte stores because it causes issues with the auto-unsubscribing features                          | :star:         |
 | [svelte/no-unknown-style-directive-property](./rules/no-unknown-style-directive-property.md)     | disallow unknown `style:property`                                                                                                      | :star:         |
+| [svelte/prefer-svelte-reactivity](./rules/prefer-svelte-reactivity.md)                           | disallow using built-in classes where a reactive alternative is provided by svelte/reactivity                                          | :star:         |
 | [svelte/require-store-callbacks-use-set-param](./rules/require-store-callbacks-use-set-param.md) | store callbacks must use `set` param                                                                                                   |                |
 | [svelte/require-store-reactive-access](./rules/require-store-reactive-access.md)                 | disallow to use of the store itself as an operand. Need to use $ prefix or get function.                                               | :star::wrench: |
 | [svelte/valid-compile](./rules/valid-compile.md)                                                 | disallow warnings when compiling.                                                                                                      |                |

docs/rules/prefer-svelte-reactivity.md

@@ -0,0 +1,68 @@
+---
+pageClass: 'rule-details'
+sidebarDepth: 0
+title: 'svelte/prefer-svelte-reactivity'
+description: 'disallow using built-in classes where a reactive alternative is provided by svelte/reactivity'
+---
+
+# svelte/prefer-svelte-reactivity
+
+> disallow using built-in classes where a reactive alternative is provided by svelte/reactivity
+
+- :exclamation: <badge text="This rule has not been released yet." vertical="middle" type="error"> **_This rule has not been released yet._** </badge>
+- :gear: This rule is included in `"plugin:svelte/recommended"`.
+
+## :book: Rule Details
+
+The built-in `Date`, `Map`, `Set`, `URL` and `URLSearchParams` classes are often used in frontend code, however, their properties and methods are not reactive. Because of that, Svelte provides reactive versions of these 5 builtins as part of the "svelte/reactivity" package. This rule reports usage of the built-in versions in Svelte code.
+
+<!--eslint-skip-->
+
+```svelte
+<script>
+  /* eslint svelte/prefer-svelte-reactivity: "error" */
+
+  import {
+    SvelteDate,
+    SvelteMap,
+    SvelteSet,
+    SvelteURL,
+    SvelteURLSearchParams
+  } from 'svelte/reactivity';
+
+  /* ✓ GOOD */
+
+  const a = new SvelteDate(8.64e15);
+  const b = new SvelteMap([
+    [1, 'one'],
+    [2, 'two']
+  ]);
+  const c = new SvelteSet([1, 2, 1, 3, 3]);
+  const d = new SvelteURL('https://svelte.dev/');
+  const e = new SvelteURLSearchParams('foo=1&bar=2');
+
+  /* ✗ BAD */
+
+  const f = new Date(8.64e15);
+  const g = new Map([
+    [1, 'one'],
+    [2, 'two']
+  ]);
+  const h = new Set([1, 2, 1, 3, 3]);
+  const i = new URL('https://svelte.dev/');
+  const j = new URLSearchParams('foo=1&bar=2');
+</script>
+```
+
+## :wrench: Options
+
+Nothing.
+
+## :books: Further Reading
+
+- [svelte/reactivity documentation](https://svelte.dev/docs/svelte/svelte-reactivity)
+
+## :mag: Implementation
+
+- [Rule source](https://github.com/sveltejs/eslint-plugin-svelte/blob/main/packages/eslint-plugin-svelte/src/rules/prefer-svelte-reactivity.ts)
+- [Test source](https://github.com/sveltejs/eslint-plugin-svelte/blob/main/packages/eslint-plugin-svelte/tests/src/rules/prefer-svelte-reactivity.ts)

packages/eslint-plugin-svelte/src/configs/flat/recommended.ts

@@ -37,6 +37,7 @@ const config: Linter.Config[] = [
 			'svelte/no-unused-svelte-ignore': 'error',
 			'svelte/no-useless-children-snippet': 'error',
 			'svelte/no-useless-mustaches': 'error',
+			'svelte/prefer-svelte-reactivity': 'error',
 			'svelte/require-each-key': 'error',
 			'svelte/require-event-dispatcher-types': 'error',
 			'svelte/require-store-reactive-access': 'error',

packages/eslint-plugin-svelte/src/rule-types.ts

@@ -306,6 +306,11 @@ export interface RuleOptions {
    * @see https://sveltejs.github.io/eslint-plugin-svelte/rules/prefer-style-directive/
    */
   'svelte/prefer-style-directive'?: Linter.RuleEntry<[]>
+  /**
+   * disallow using built-in classes where a reactive alternative is provided by svelte/reactivity
+   * @see https://sveltejs.github.io/eslint-plugin-svelte/rules/prefer-svelte-reactivity/
+   */
+  'svelte/prefer-svelte-reactivity'?: Linter.RuleEntry<[]>
   /**
    * require keyed `{#each}` block
    * @see https://sveltejs.github.io/eslint-plugin-svelte/rules/require-each-key/

packages/eslint-plugin-svelte/src/rules/prefer-svelte-reactivity.ts

@@ -0,0 +1,72 @@
+import { ReferenceTracker } from '@eslint-community/eslint-utils';
+import { getSourceCode } from '../utils/compat.js';
+import { createRule } from '../utils/index.js';
+
+export default createRule('prefer-svelte-reactivity', {
+	meta: {
+		docs: {
+			description:
+				'disallow using built-in classes where a reactive alternative is provided by svelte/reactivity',
+			category: 'Possible Errors',
+			recommended: true
+		},
+		schema: [],
+		messages: {
+			dateUsed: 'Found a usage of the built-in Date class. Use a SvelteDate instead.',
+			mapUsed: 'Found a usage of the built-in Map class. Use a SvelteMap instead.',
+			setUsed: 'Found a usage of the built-in Set class. Use a SvelteSet instead.',
+			urlUsed: 'Found a usage of the built-in URL class. Use a SvelteURL instead.',
+			urlSearchParamsUsed:
+				'Found a usage of the built-in URLSearchParams class. Use a SvelteURLSearchParams instead.'
+		},
+		type: 'problem', // 'problem', or 'layout',
+		conditions: [
+			{
+				svelteVersions: ['5'],
+				svelteFileTypes: ['.svelte', '.svelte.[js|ts]']
+			}
+		]
+	},
+	create(context) {
+		return {
+			Program() {
+				const referenceTracker = new ReferenceTracker(
+					getSourceCode(context).scopeManager.globalScope!
+				);
+				for (const { node, path } of referenceTracker.iterateGlobalReferences({
+					Date: {
+						[ReferenceTracker.CONSTRUCT]: true
+					},
+					Map: {
+						[ReferenceTracker.CONSTRUCT]: true
+					},
+					Set: {
+						[ReferenceTracker.CONSTRUCT]: true
+					},
+					URL: {
+						[ReferenceTracker.CALL]: true,
+						[ReferenceTracker.CONSTRUCT]: true,
+						[ReferenceTracker.READ]: true
+					},
+					URLSearchParams: {
+						[ReferenceTracker.CALL]: true,
+						[ReferenceTracker.CONSTRUCT]: true,
+						[ReferenceTracker.READ]: true
+					}
+				})) {
+					const typeToMessageId: Record<string, string> = {
+						Date: 'dateUsed',
+						Map: 'mapUsed',
+						Set: 'setUsed',
+						URL: 'urlUsed',
+						URLSearchParams: 'urlSearchParamsUsed'
+					};
+					context.report({
+						messageId: typeToMessageId[path[0]],
+						node
+					});
+				}
+			}
+		};
+	}
+});

packages/eslint-plugin-svelte/src/utils/rules.ts

@@ -60,6 +60,7 @@ import preferClassDirective from '../rules/prefer-class-directive.js';
 import preferConst from '../rules/prefer-const.js';
 import preferDestructuredStoreProps from '../rules/prefer-destructured-store-props.js';
 import preferStyleDirective from '../rules/prefer-style-directive.js';
+import preferSvelteReactivity from '../rules/prefer-svelte-reactivity.js';
 import requireEachKey from '../rules/require-each-key.js';
 import requireEventDispatcherTypes from '../rules/require-event-dispatcher-types.js';
 import requireOptimizedStyleAttribute from '../rules/require-optimized-style-attribute.js';
@@ -135,6 +136,7 @@ export const rules = [
 	preferConst,
 	preferDestructuredStoreProps,
 	preferStyleDirective,
+	preferSvelteReactivity,
 	requireEachKey,
 	requireEventDispatcherTypes,
 	requireOptimizedStyleAttribute,

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/date01-input.svelte

@@ -0,0 +1,5 @@
+<script>
+  const variable = new Date(8.64e15);
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/map01-input.svelte

@@ -0,0 +1,5 @@
+<script>
+  const variable = new Map([[1, "one"], [2, "two"]]);
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/set01-input.svelte

@@ -0,0 +1,5 @@
+<script>
+  const variable = new Set([1, 2, 1, 3, 3]);
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url-search-params01-input.svelte

@@ -0,0 +1,5 @@
+<script>
+  const variable = new URLSearchParams("foo=1&bar=2");
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/invalid/url01-input.svelte

@@ -0,0 +1,5 @@
+<script>
+  const variable = new URL("https://svelte.dev/");
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-date01-input.svelte

@@ -0,0 +1,7 @@
+<script>
+  import { SvelteDate as Date } from "svelte/reactivity";
+
+  const variable = new Date(8.64e15);
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-map01-input.svelte

@@ -0,0 +1,7 @@
+<script>
+  import { SvelteMap as Map } from "svelte/reactivity";
+
+  const variable = new Map([[1, "one"], [2, "two"]]);
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-set01-input.svelte

@@ -0,0 +1,7 @@
+<script>
+  import { SvelteSet as Set } from "svelte/reactivity";
+
+  const variable = new Set([1, 2, 1, 3, 3]);
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-url-search-params01-input.svelte

@@ -0,0 +1,7 @@
+<script>
+  import { SvelteURLSearchParams as URLSearchParams } from "svelte/reactivity";
+
+  const variable = new URLSearchParams("foo=1&bar=2");
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/aliased-url01-input.svelte

@@ -0,0 +1,7 @@
+<script>
+  import { SvelteURL as URL } from "svelte/reactivity";
+
+  const variable = new URL("https://svelte.dev/");
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-date01-input.svelte

@@ -0,0 +1,7 @@
+<script>
+  import { SvelteDate } from "svelte/reactivity";
+
+  const variable = new SvelteDate(8.64e15);
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-map01-input.svelte

@@ -0,0 +1,7 @@
+<script>
+  import { SvelteMap } from "svelte/reactivity";
+
+  const variable = new SvelteMap([[1, "one"], [2, "two"]]);
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-set01-input.svelte

@@ -0,0 +1,7 @@
+<script>
+  import { SvelteSet } from "svelte/reactivity";
+
+  const variable = new SvelteSet([1, 2, 1, 3, 3]);
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-url-search-params01-input.svelte

@@ -0,0 +1,7 @@
+<script>
+  import { SvelteURLSearchParams } from "svelte/reactivity";
+
+  const variable = new SvelteURLSearchParams("foo=1&bar=2");
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/svelte-url01-input.svelte

@@ -0,0 +1,7 @@
+<script>
+  import { SvelteURL } from "svelte/reactivity";
+
+  const variable = new SvelteURL("https://svelte.dev/");
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-date01-input.svelte

@@ -0,0 +1,7 @@
+<script>
+  import { Date } from "package";
+
+  const variable = new Date(8.64e15);
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-map01-input.svelte

@@ -0,0 +1,7 @@
+<script>
+  import { Map } from "package";
+
+  const variable = new Map([[1, "one"], [2, "two"]]);
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-set01-input.svelte

@@ -0,0 +1,7 @@
+<script>
+  import { Set } from "package";
+
+  const variable = new Set([1, 2, 1, 3, 3]);
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-url-search-params01-input.svelte

@@ -0,0 +1,7 @@
+<script>
+  import { URLSearchParams } from "package";
+
+  const variable = new URLSearchParams("foo=1&bar=2");
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/fixtures/rules/prefer-svelte-reactivity/valid/unrelated-url01-input.svelte

@@ -0,0 +1,7 @@
+<script>
+  import { URL } from "package";
+
+  const variable = new URL("https://svelte.dev/");
+</script>
+
+{variable}

packages/eslint-plugin-svelte/tests/src/rules/prefer-svelte-reactivity.ts

@@ -0,0 +1,16 @@
+import { RuleTester } from '../../utils/eslint-compat.js';
+import rule from '../../../src/rules/prefer-svelte-reactivity.js';
+import { loadTestCases } from '../../utils/utils.js';
+
+const tester = new RuleTester({
+	languageOptions: {
+		ecmaVersion: 2020,
+		globals: {
+			URL: "readonly",
+			URLSearchParams: "readonly",
+		},
+		sourceType: 'module'
+	}
+});
+
+tester.run('prefer-svelte-reactivity', rule as any, loadTestCases('prefer-svelte-reactivity'));