feat: add no-export-load-in-svelte-module-in-kit-pages

.changeset/orange-months-sparkle.md

@@ -0,0 +1,5 @@
+---
+"eslint-plugin-svelte": minor
+---
+
+feat: add `no-export-load-in-svelte-module-in-kit-pages` rule

README.md

@@ -266,6 +266,7 @@ These rules relate to possible syntax or logic errors in Svelte code:
 | [svelte/no-dupe-else-if-blocks](https://ota-meshi.github.io/eslint-plugin-svelte/rules/no-dupe-else-if-blocks/) | disallow duplicate conditions in `{#if}` / `{:else if}` chains | :star: |
 | [svelte/no-dupe-style-properties](https://ota-meshi.github.io/eslint-plugin-svelte/rules/no-dupe-style-properties/) | disallow duplicate style properties | :star: |
 | [svelte/no-dynamic-slot-name](https://ota-meshi.github.io/eslint-plugin-svelte/rules/no-dynamic-slot-name/) | disallow dynamic slot name | :star::wrench: |
+| [svelte/no-export-load-in-svelte-module-in-kit-pages](https://ota-meshi.github.io/eslint-plugin-svelte/rules/no-export-load-in-svelte-module-in-kit-pages/) | Disallow exporting load functions in `*.svelte` module in Svelte Kit page components. | :star: |
 | [svelte/no-not-function-handler](https://ota-meshi.github.io/eslint-plugin-svelte/rules/no-not-function-handler/) | disallow use of not function in event handler | :star: |
 | [svelte/no-object-in-text-mustaches](https://ota-meshi.github.io/eslint-plugin-svelte/rules/no-object-in-text-mustaches/) | disallow objects in text mustache interpolation | :star: |
 | [svelte/no-shorthand-style-property-overrides](https://ota-meshi.github.io/eslint-plugin-svelte/rules/no-shorthand-style-property-overrides/) | disallow shorthand style properties that override related longhand properties | :star: |

docs/rules.md

@@ -19,6 +19,7 @@ These rules relate to possible syntax or logic errors in Svelte code:
 | [svelte/no-dupe-else-if-blocks](./rules/no-dupe-else-if-blocks.md) | disallow duplicate conditions in `{#if}` / `{:else if}` chains | :star: |
 | [svelte/no-dupe-style-properties](./rules/no-dupe-style-properties.md) | disallow duplicate style properties | :star: |
 | [svelte/no-dynamic-slot-name](./rules/no-dynamic-slot-name.md) | disallow dynamic slot name | :star::wrench: |
+| [svelte/no-export-load-in-svelte-module-in-kit-pages](./rules/no-export-load-in-svelte-module-in-kit-pages.md) | Disallow exporting load functions in `*.svelte` module in Svelte Kit page components. | :star: |
 | [svelte/no-not-function-handler](./rules/no-not-function-handler.md) | disallow use of not function in event handler | :star: |
 | [svelte/no-object-in-text-mustaches](./rules/no-object-in-text-mustaches.md) | disallow objects in text mustache interpolation | :star: |
 | [svelte/no-shorthand-style-property-overrides](./rules/no-shorthand-style-property-overrides.md) | disallow shorthand style properties that override related longhand properties | :star: |

docs/rules/no-export-load-in-svelte-module-in-kit-pages.md

@@ -0,0 +1,55 @@
+---
+pageClass: "rule-details"
+sidebarDepth: 0
+title: "svelte/no-export-load-in-svelte-module-in-kit-pages"
+description: "Disallow exporting load functions in `*.svelte` module in Svelte Kit page components."
+---
+
+# svelte/no-export-load-in-svelte-module-in-kit-pages
+
+> Disallow exporting load functions in `*.svelte` module in Svelte Kit page components.
+
+- :gear: This rule is included in `"plugin:svelte/recommended"`.
+
+## :book: Rule Details
+
+This rule reports unexpected exported `load` function at `<script context="module">`.
+At SvelteKit v1.0.0-next.405, `load` function has been moved into a separate file — `+page.js` for pages, `+layout.js` for layouts.
+And the API has changed.
+
+<ESLintCodeBlock>
+
+<!--eslint-skip-->
+
+```svelte
+<script context="module">
+  /* eslint svelte/no-export-load-in-svelte-module-in-kit-pages: "error" */
+  /* ✓ GOOD  */
+  export function foo() {}
+  export function bar() {}
+  /* ✗ BAD  */
+  export function load() {}
+  // export const load = () => {}
+</script>
+```
+
+</ESLintCodeBlock>
+
+## :wrench: Options
+
+```json
+{
+  "svelte/no-export-load-in-svelte-module-in-kit-pages": ["error", {}]
+}
+```
+
+-
+
+## :books: Further Reading
+
+- [SvelteKit Migration Guide (v1.0.0-next.405)](https://github.com/sveltejs/kit/discussions/5774#discussioncomment-3292693)
+
+## :mag: Implementation
+
+- [Rule source](https://github.com/ota-meshi/eslint-plugin-svelte/blob/main/src/rules/no-export-load-in-svelte-module-in-kit-pages.ts)
+- [Test source](https://github.com/ota-meshi/eslint-plugin-svelte/blob/main/tests/src/rules/no-export-load-in-svelte-module-in-kit-pages.ts)

package.json

@@ -174,7 +174,7 @@
     "access": "public"
   },
   "typeCoverage": {
-    "atLeast": 98.71,
+    "atLeast": 98.7,
     "cache": true,
     "detail": true,
     "ignoreAsAssertion": true,

src/configs/recommended.ts

@@ -12,6 +12,7 @@ export = {
     "svelte/no-dupe-else-if-blocks": "error",
     "svelte/no-dupe-style-properties": "error",
     "svelte/no-dynamic-slot-name": "error",
+    "svelte/no-export-load-in-svelte-module-in-kit-pages": "error",
     "svelte/no-inner-declarations": "error",
     "svelte/no-not-function-handler": "error",
     "svelte/no-object-in-text-mustaches": "error",

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

@@ -0,0 +1,55 @@
+import type * as ESTree from "estree"
+import { createRule } from "../utils"
+import fs from "fs"
+
+const hasSvelteKit = (() => {
+  try {
+    const packageJson = JSON.parse(fs.readFileSync("./package.json", "utf8"))
+    return Boolean(
+      packageJson.dependencies["@sveltejs/kit"] ??
+        packageJson.devDependencies["@sveltejs/kit"],
+    )
+  } catch (_e) {
+    return false
+  }
+})()
+
+export default createRule("no-export-load-in-svelte-module-in-kit-pages", {
+  meta: {
+    docs: {
+      description:
+        "Disallow exporting load functions in `*.svelte` module in Svelte Kit page components.",
+      category: "Possible Errors",
+      recommended: true,
+    },
+    schema: [],
+    messages: {
+      unexpected:
+        "Disallow exporting load functions in `*.svelte` module in Svelte Kit page components.",
+    },
+    type: "problem",
+  },
+  create(context) {
+    if (!hasSvelteKit) return {}
+    let isModule = false
+    return {
+      // <script context="module">
+      [`Program > SvelteScriptElement > SvelteStartTag > SvelteAttribute > SvelteLiteral[value="module"]`]:
+        () => {
+          isModule = true
+        },
+
+      // export function load() {}
+      // export const load = () => {}
+      [`ExportNamedDeclaration :matches(FunctionDeclaration, VariableDeclaration > VariableDeclarator) > Identifier[name="load"]`]:
+        (node: ESTree.Identifier) => {
+          if (!isModule) return {}
+          return context.report({
+            node,
+            loc: node.loc!,
+            messageId: "unexpected",
+          })
+        },
+    }
+  },
+})

src/utils/rules.ts

@@ -15,6 +15,7 @@ import noAtHtmlTags from "../rules/no-at-html-tags"
 import noDupeElseIfBlocks from "../rules/no-dupe-else-if-blocks"
 import noDupeStyleProperties from "../rules/no-dupe-style-properties"
 import noDynamicSlotName from "../rules/no-dynamic-slot-name"
+import noExportLoadInSvelteModuleInKitPages from "../rules/no-export-load-in-svelte-module-in-kit-pages"
 import noExtraReactiveCurlies from "../rules/no-extra-reactive-curlies"
 import noInnerDeclarations from "../rules/no-inner-declarations"
 import noNotFunctionHandler from "../rules/no-not-function-handler"
@@ -58,6 +59,7 @@ export const rules = [
   noDupeElseIfBlocks,
   noDupeStyleProperties,
   noDynamicSlotName,
+  noExportLoadInSvelteModuleInKitPages,
   noExtraReactiveCurlies,
   noInnerDeclarations,
   noNotFunctionHandler,

tests/fixtures/rules/html-self-closing/invalid/presets/html/preset-html-errors.yaml

@@ -0,0 +1,16 @@
+- message: Disallow self-closing on HTML elements.
+  line: 3
+  column: 3
+  suggestions: null
+- message: Require self-closing on HTML void elements.
+  line: 4
+  column: 3
+  suggestions: null
+- message: Disallow self-closing on Svelte custom components.
+  line: 5
+  column: 3
+  suggestions: null
+- message: Require self-closing on Svelte special elements.
+  line: 8
+  column: 1
+  suggestions: null

tests/fixtures/rules/html-self-closing/invalid/presets/none/preset-none-errors.yaml

@@ -0,0 +1,16 @@
+- message: Disallow self-closing on HTML elements.
+  line: 3
+  column: 3
+  suggestions: null
+- message: Disallow self-closing on Svelte custom components.
+  line: 4
+  column: 3
+  suggestions: null
+- message: Disallow self-closing on HTML void elements.
+  line: 5
+  column: 3
+  suggestions: null
+- message: Disallow self-closing on Svelte special elements.
+  line: 8
+  column: 1
+  suggestions: null

tests/fixtures/rules/no-export-load-in-svelte-module-in-kit-pages/invalid/test01-errors.yaml

@@ -0,0 +1,4 @@
+- message: "Disallow exporting load functions in `*.svelte` module in Svelte Kit page components."
+  line: 2
+  column: 19
+  suggestions: null

tests/fixtures/rules/no-export-load-in-svelte-module-in-kit-pages/invalid/test01-input.svelte

@@ -0,0 +1,3 @@
+<script context="module">
+  export function load() {}
+</script>

tests/fixtures/rules/no-export-load-in-svelte-module-in-kit-pages/invalid/test02-errors.yaml

@@ -0,0 +1,4 @@
+- message: "Disallow exporting load functions in `*.svelte` module in Svelte Kit page components."
+  line: 2
+  column: 16
+  suggestions: null

tests/fixtures/rules/no-export-load-in-svelte-module-in-kit-pages/invalid/test02-input.svelte

@@ -0,0 +1,3 @@
+<script context="module">
+  export const load = () => {}
+</script>

tests/fixtures/rules/no-export-load-in-svelte-module-in-kit-pages/valid/test01-input.svelte

@@ -0,0 +1,3 @@
+<script>
+  export function load() {}
+</script>

tests/fixtures/rules/no-export-load-in-svelte-module-in-kit-pages/valid/test02-input.svelte

@@ -0,0 +1,3 @@
+<script>
+  export const load = () => {}
+</script>

tests/fixtures/rules/no-export-load-in-svelte-module-in-kit-pages/valid/test03-input.svelte

@@ -0,0 +1,3 @@
+<script context="module">
+  function load() {}
+</script>

tests/fixtures/rules/no-export-load-in-svelte-module-in-kit-pages/valid/test04-input.svelte

@@ -0,0 +1,3 @@
+<script context="module">
+  const load = () => {}
+</script>

tests/fixtures/rules/no-export-load-in-svelte-module-in-kit-pages/valid/test05-input.svelte

@@ -0,0 +1,3 @@
+<script context="module">
+  export function foo() {}
+</script>

tests/src/rules/no-export-load-in-svelte-module-in-kit-pages.ts

@@ -0,0 +1,16 @@
+import { RuleTester } from "eslint"
+import rule from "../../../src/rules/no-export-load-in-svelte-module-in-kit-pages"
+import { loadTestCases } from "../../utils/utils"
+
+const tester = new RuleTester({
+  parserOptions: {
+    ecmaVersion: 2020,
+    sourceType: "module",
+  },
+})
+
+tester.run(
+  "no-export-load-in-svelte-module-in-kit-pages",
+  rule as any,
+  loadTestCases("no-export-load-in-svelte-module-in-kit-pages"),
+)