feat: add control for executing rules based on Svelte/SvelteKit context

.changeset/blue-swans-give.md

@@ -0,0 +1,5 @@
+---
+'eslint-plugin-svelte': minor
+---
+
+feat: Implement util to conditionally run lint based on Svelte version and SvelteKit routes etc

packages/eslint-plugin-svelte/src/rules/no-export-load-in-svelte-module-in-kit-pages.ts

@@ -1,6 +1,5 @@
 import type { TSESTree } from '@typescript-eslint/types';
 import { createRule } from '../utils/index.js';
-import { isKitPageComponent } from '../utils/svelte-kit.js';
 
 export default createRule('no-export-load-in-svelte-module-in-kit-pages', {
 	meta: {
@@ -8,7 +7,7 @@
 			description:
 				'disallow exporting load functions in `*.svelte` module in SvelteKit page components.',
 			category: 'Possible Errors',
 			// TODO Switch to recommended in the major version.
 			recommended: false
 		},
 		schema: [],
@@ -16,12 +15,14 @@
 			unexpected:
 				'disallow exporting load functions in `*.svelte` module in SvelteKit page components.'
 		},
-		type: 'problem'
+		type: 'problem',
+		conditions: [
+			{
+				svelteKitFileTypes: ['+page.svelte', '+error.svelte', '+layout.svelte']
+			}
+		]
 	},
 	create(context) {
-		if (!isKitPageComponent(context)) {
-			return {};
-		}
 		let isModule = false;
 		return {
 			// <script context="module">

packages/eslint-plugin-svelte/src/rules/valid-prop-names-in-kit-pages.ts

@@ -1,7 +1,6 @@
 import type { AST } from 'svelte-eslint-parser';
 import type { TSESTree } from '@typescript-eslint/types';
 import { createRule } from '../utils/index.js';
-import { isKitPageComponent } from '../utils/svelte-kit.js';
 import type { RuleContext } from '../types.js';
 
 const EXPECTED_PROP_NAMES = ['data', 'errors', 'form', 'snapshot'];
@@ -35,10 +34,14 @@ export default createRule('valid-prop-names-in-kit-pages', {
 		messages: {
 			unexpected: 'disallow props other than data or errors in SvelteKit page components.'
 		},
-		type: 'problem'
+		type: 'problem',
+		conditions: [
+			{
+				svelteKitFileTypes: ['+page.svelte', '+error.svelte', '+layout.svelte']
+			}
+		]
 	},
 	create(context) {
-		if (!isKitPageComponent(context)) return {};
 		let isScript = false;
 		return {
 			// <script>

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

@@ -8,6 +8,7 @@ import type { Root as SelectorRoot, Node as SelectorNode } from 'postcss-selecto
 import type { ASTNode, ASTNodeWithParent, ASTNodeListener } from './types-for-node.js';
 import type * as TS from 'typescript';
 import type { SourceLocation } from 'svelte-eslint-parser/lib/ast/common.js';
+import type { SvelteContext } from './utils/svelte-context.js';
 
 export type { ASTNode, ASTNodeWithParent, ASTNodeListener };
 export interface RuleListener extends ASTNodeListener {
@@ -108,6 +109,18 @@ export interface PartialRuleMetaData {
 	deprecated?: boolean;
 	replacedBy?: string[] | { note: string };
 	type: 'problem' | 'suggestion' | 'layout';
+	/**
+	 * Conditions to determine whether this rule should be applied.
+	 * Multiple conditions can be specified as array, and the rule will be applied if any one of them matches (logical OR).
+	 * If not specified, the rule will be applied to all files.
+	 */
+	conditions?: {
+		svelteVersions?: SvelteContext['svelteVersion'][];
+		svelteFileTypes?: SvelteContext['svelteFileType'][];
+		runes?: SvelteContext['runes'][];
+		svelteKitVersions?: SvelteContext['svelteKitVersion'][];
+		svelteKitFileTypes?: SvelteContext['svelteKitFileType'][];
+	}[];
 }
 
 export type RuleContext = {

packages/eslint-plugin-svelte/src/utils/get-package-json.ts

@@ -14,7 +14,8 @@ type PackageJson = {
 };
 
 const isRunOnBrowser = !fs.readFileSync;
-const cache = createCache<PackageJson | null>();
+const packageJsonCache = createCache<PackageJson | null>();
+const packageJsonsCache = createCache<PackageJson[]>();
 
 /**
  * Reads the `package.json` data in a given path.
@@ -49,34 +50,37 @@ function readPackageJson(dir: string): PackageJson | null {
  * @returns A found `package.json` data or `null`.
  *      This object have additional property `filePath`.
  */
-export function getPackageJson(startPath = 'a.js'): PackageJson | null {
-	if (isRunOnBrowser) return null;
+export function getPackageJsons(startPath = 'a.js'): PackageJson[] {
+	if (isRunOnBrowser) return [];
+
+	const cached = packageJsonsCache.get(startPath);
+	if (cached) {
+		return cached;
+	}
+
+	const packageJsons: PackageJson[] = [];
 	const startDir = path.dirname(path.resolve(startPath));
 	let dir = startDir;
 	let prevDir = '';
 	let data = null;
 
 	do {
-		data = cache.get(dir);
+		data = packageJsonCache.get(dir);
 		if (data) {
-			if (dir !== startDir) {
-				cache.set(startDir, data);
-			}
-			return data;
+			packageJsons.push(data);
 		}
 
 		data = readPackageJson(dir);
 		if (data) {
-			cache.set(dir, data);
-			cache.set(startDir, data);
-			return data;
+			packageJsonCache.set(dir, data);
+			packageJsons.push(data);
 		}
 
 		// Go to next.
 		prevDir = dir;
 		dir = path.resolve(dir, '..');
 	} while (dir !== prevDir);
 
-	cache.set(startDir, null);
-	return null;
+	packageJsonsCache.set(startDir, packageJsons);
+	return packageJsons;
 }

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

@@ -1,4 +1,50 @@
-import type { RuleModule, PartialRuleModule } from '../types.js';
+import type { RuleModule, PartialRuleModule, PartialRuleMetaData, RuleContext } from '../types.js';
+import { getSvelteContext, type SvelteContext } from '../utils/svelte-context.js';
+
+function doesNotSatisfy<T>(actual: T, expected?: T[]): boolean {
+	if (expected == null || expected.length === 0) {
+		return false;
+	}
+
+	return !expected.includes(actual);
+}
+
+function satisfiesCondition(
+	condition: NonNullable<PartialRuleMetaData['conditions']>[number],
+	svelteContext: SvelteContext
+): boolean {
+	if (
+		doesNotSatisfy(svelteContext.svelteVersion, condition.svelteVersions) ||
+		doesNotSatisfy(svelteContext.svelteFileType, condition.svelteFileTypes) ||
+		doesNotSatisfy(svelteContext.runes, condition.runes) ||
+		doesNotSatisfy(svelteContext.svelteKitVersion, condition.svelteKitVersions) ||
+		doesNotSatisfy(svelteContext.svelteKitFileType, condition.svelteKitFileTypes)
+	) {
+		return false;
+	}
+
+	return true;
+}
+
+// export for testing
+export function shouldRun(
+	svelteContext: SvelteContext | null,
+	conditions: PartialRuleMetaData['conditions']
+): boolean {
+	// If svelteContext is null, it means the rule might be executed based on the analysis result of a different parser.
+	// In this case, always execute the rule.
+	if (svelteContext == null || conditions == null || conditions.length === 0) {
+		return true;
+	}
+
+	for (const condition of conditions) {
+		if (satisfiesCondition(condition, svelteContext)) {
+			return true;
+		}
+	}
+
+	return false;
+}
 
 /**
  * Define the rule.
@@ -16,6 +62,14 @@ export function createRule(ruleName: string, rule: PartialRuleModule): RuleModul
 				ruleName
 			}
 		},
-		create: rule.create as never
+		create(context: RuleContext) {
+			const { conditions } = rule.meta;
+			const svelteContext = getSvelteContext(context);
+			if (!shouldRun(svelteContext, conditions)) {
+				return {};
+			}
+
+			return rule.create(context);
+		}
 	};
 }