feat: no-not-data-props-in-kit-pages (#283)

* feat: add no-not-data-props-in-kit-pages

* chore: run yarn upadte

* fix: bug

* chore: add todo

* chore: add changeset

* chore: update document

* fix: strict kit page component check

* chore: change rule name

* fix: test

* fix: change file name

* fix: logic

* fix: regexp

Author: baseballyama

.changeset/purple-coats-vanish.md

@@ -0,0 +1,5 @@
+---
+"eslint-plugin-svelte": minor
+---
+
+feat: add `svelte/valid-prop-names-in-kit-pages` rule

README.md

@@ -309,6 +309,7 @@ These rules relate to possible syntax or logic errors in Svelte code:
 | [svelte/no-unknown-style-directive-property](https://ota-meshi.github.io/eslint-plugin-svelte/rules/no-unknown-style-directive-property/) | disallow unknown `style:property` | :star: |
 | [svelte/require-store-callbacks-use-set-param](https://ota-meshi.github.io/eslint-plugin-svelte/rules/require-store-callbacks-use-set-param/) | store callbacks must use `set` param |  |
 | [svelte/valid-compile](https://ota-meshi.github.io/eslint-plugin-svelte/rules/valid-compile/) | disallow warnings when compiling. | :star: |
+| [svelte/valid-prop-names-in-kit-pages](https://ota-meshi.github.io/eslint-plugin-svelte/rules/valid-prop-names-in-kit-pages/) | disallow props other than data or errors in Svelte Kit page components. |  |
 
 ## Security Vulnerability
 

docs/rules.md

@@ -27,6 +27,7 @@ These rules relate to possible syntax or logic errors in Svelte code:
 | [svelte/no-unknown-style-directive-property](./rules/no-unknown-style-directive-property.md) | disallow unknown `style:property` | :star: |
 | [svelte/require-store-callbacks-use-set-param](./rules/require-store-callbacks-use-set-param.md) | store callbacks must use `set` param |  |
 | [svelte/valid-compile](./rules/valid-compile.md) | disallow warnings when compiling. | :star: |
+| [svelte/valid-prop-names-in-kit-pages](./rules/valid-prop-names-in-kit-pages.md) | disallow props other than data or errors in Svelte Kit page components. |  |
 
 ## Security Vulnerability
 

docs/rules/valid-prop-names-in-kit-pages.md

@@ -0,0 +1,65 @@
+---
+pageClass: "rule-details"
+sidebarDepth: 0
+title: "svelte/valid-prop-names-in-kit-pages"
+description: "disallow props other than data or errors in Svelte Kit page components."
+---
+
+# svelte/valid-prop-names-in-kit-pages
+
+> disallow props other than data or errors in Svelte Kit page components.
+
+- :exclamation: <badge text="This rule has not been released yet." vertical="middle" type="error"> **_This rule has not been released yet._** </badge>
+
+## :book: Rule Details
+
+This rule reports unexpected exported variables at `<script>`.<br>
+At SvelteKit v1.0.0-next.405, instead of having multiple props corresponding to the props returned from a load function, page components now have a single data prop.
+
+<script>
+  const config = {settings: {
+    kit: {
+      files: {
+        routes: "",
+      },
+    },
+  },
+  }
+</script>
+
+<ESLintCodeBlock config="{config}">
+
+<!--eslint-skip-->
+
+```svelte
+<script>
+  /* eslint svelte/valid-prop-names-in-kit-pages: "error" */
+  /** ✓ GOOD */
+  export let data
+  export let errors
+  // export let { data, errors } = { data: {}, errors: {} }
+
+  /** ✗ BAD */
+  export let foo
+  export let bar
+  export let { baz, qux } = data
+  export let { data: data2, errors: errors2 } = { data: {}, errors: {} }
+</script>
+
+{foo}, {bar}
+```
+
+</ESLintCodeBlock>
+
+## :wrench: Options
+
+Nothing. But if use are using not default routes folder, please set configuration according to the [user guide](../user-guide.md#settings-kit).
+
+## :books: Further Reading
+
+- [SvelteKit Migration Guide (v1.0.0-next.405)](https://github.com/sveltejs/kit/discussions/5774#discussioncomment-3292707)
+
+## :mag: Implementation
+
+- [Rule source](https://github.com/ota-meshi/eslint-plugin-svelte/blob/main/src/rules/valid-prop-names-in-kit-pages.ts)
+- [Test source](https://github.com/ota-meshi/eslint-plugin-svelte/blob/main/tests/src/rules/valid-prop-names-in-kit-pages.ts)

src/rules/valid-prop-names-in-kit-pages.ts

@@ -0,0 +1,83 @@
+import type { AST } from "svelte-eslint-parser"
+import type * as ESTree from "estree"
+import { createRule } from "../utils"
+import { isKitPageComponent } from "../utils/svelte-kit"
+
+const EXPECTED_PROP_NAMES = ["data", "errors"]
+
+export default createRule("valid-prop-names-in-kit-pages", {
+  meta: {
+    docs: {
+      description:
+        "disallow props other than data or errors in Svelte Kit page components.",
+      category: "Possible Errors",
+      // TODO Switch to recommended in the major version.
+      recommended: false,
+    },
+    schema: [],
+    messages: {
+      unexpected:
+        "disallow props other than data or errors in Svelte Kit page components.",
+    },
+    type: "problem",
+  },
+  create(context) {
+    if (!isKitPageComponent(context)) return {}
+    let isScript = false
+    return {
+      // <script>
+      "Program > SvelteScriptElement > SvelteStartTag": (
+        node: AST.SvelteStartTag,
+      ) => {
+        // except for <script context="module">
+        isScript = !node.attributes.some(
+          (a) =>
+            a.type === "SvelteAttribute" &&
+            a.key.name === "context" &&
+            a.value.some(
+              (v) => v.type === "SvelteLiteral" && v.value === "module",
+            ),
+        )
+      },
+
+      // </script>
+      "Program > SvelteScriptElement:exit": () => {
+        isScript = false
+      },
+
+      "ExportNamedDeclaration > VariableDeclaration > VariableDeclarator": (
+        node: ESTree.VariableDeclarator,
+      ) => {
+        if (!isScript) return
+
+        // export let foo
+        if (node.id.type === "Identifier") {
+          if (!EXPECTED_PROP_NAMES.includes(node.id.name)) {
+            context.report({
+              node,
+              loc: node.loc!,
+              messageId: "unexpected",
+            })
+          }
+          return
+        }
+
+        // export let { xxx, yyy } = zzz
+        if (node.id.type !== "ObjectPattern") return
+        for (const p of node.id.properties) {
+          if (
+            p.type === "Property" &&
+            p.value.type === "Identifier" &&
+            !EXPECTED_PROP_NAMES.includes(p.value.name)
+          ) {
+            context.report({
+              node: p.value,
+              loc: p.value.loc!,
+              messageId: "unexpected",
+            })
+          }
+        }
+      },
+    }
+  },
+})

src/utils/rules.ts

@@ -42,6 +42,7 @@ import sortAttributes from "../rules/sort-attributes"
 import spacedHtmlComment from "../rules/spaced-html-comment"
 import system from "../rules/system"
 import validCompile from "../rules/valid-compile"
+import validPropNamesInKitPages from "../rules/valid-prop-names-in-kit-pages"
 
 export const rules = [
   typescriptEslintNoUnnecessaryCondition,
@@ -87,4 +88,5 @@ export const rules = [
   spacedHtmlComment,
   system,
   validCompile,
+  validPropNamesInKitPages,
 ] as RuleModule[]

src/utils/svelte-kit.ts

@@ -23,7 +23,12 @@ export function isKitPageComponent(context: RuleContext): boolean {
     "src/routes"
   const filePath = context.getFilename()
   const projectRootDir = getProjectRootDir(context.getFilename()) ?? ""
-  return filePath.startsWith(path.join(projectRootDir, routes))
+  const fileName = filePath.split("/").pop() || filePath
+  return (
+    filePath.startsWith(path.join(projectRootDir, routes)) &&
+    // MEMO: check only `+` and file extension for maintainability
+    Boolean(/^\+.+\.svelte$/.test(fileName))
+  )
 }
 
 /**

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

@@ -0,0 +1,24 @@
+- message: disallow props other than data or errors in Svelte Kit page components.
+  line: 2
+  column: 14
+  suggestions: null
+- message: disallow props other than data or errors in Svelte Kit page components.
+  line: 3
+  column: 14
+  suggestions: null
+- message: disallow props other than data or errors in Svelte Kit page components.
+  line: 4
+  column: 16
+  suggestions: null
+- message: disallow props other than data or errors in Svelte Kit page components.
+  line: 4
+  column: 21
+  suggestions: null
+- message: disallow props other than data or errors in Svelte Kit page components.
+  line: 5
+  column: 22
+  suggestions: null
+- message: disallow props other than data or errors in Svelte Kit page components.
+  line: 5
+  column: 37
+  suggestions: null

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

@@ -0,0 +1,8 @@
+<script>
+  export let foo
+  export let bar
+  export let { baz, qux } = data
+  export let { data: data2, errors: errors2 } = { data: {}, errors: {} }
+</script>
+
+{foo}, {bar}

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

@@ -0,0 +1,11 @@
+{
+  "settings": {
+    "svelte": {
+      "kit": {
+        "files": {
+          "routes": "tests/fixtures"
+        }
+      }
+    }
+  }
+}

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

@@ -0,0 +1,6 @@
+<script>
+  export let data
+  export let errors
+</script>
+
+{data}, {errors}

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

@@ -0,0 +1,8 @@
+<script context="module">
+  export let data
+  export let errors
+  export let foo
+  export let bar
+</script>
+
+{data}, {errors}, {foo}, {bar}

tests/fixtures/rules/no-export-load-in-svelte-module-in-kit-pages/valid/test010-input.svelte renamed to tests/fixtures/rules/no-export-load-in-svelte-module-in-kit-pages/valid/+test010-input.svelte

@@ -0,0 +1,5 @@
+<script context="module">
+  export let { data, errors } = { data: {}, errors: {} }
+</script>
+
+{data}, {errors}

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

@@ -0,0 +1,5 @@
+<script context="module">
+  export let { data2: data, errors2: errors } = { data2: {}, errors2: {} }
+</script>
+
+{data}, {errors}

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

@@ -0,0 +1,11 @@
+{
+  "settings": {
+    "svelte": {
+      "kit": {
+        "files": {
+          "routes": "tests/fixtures"
+        }
+      }
+    }
+  }
+}

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

@@ -0,0 +1,8 @@
+<script>
+  export let data
+  export let errors
+  export let foo
+  export let bar
+</script>
+
+{data}, {errors}, {foo}, {bar}

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

@@ -0,0 +1,16 @@
+import { RuleTester } from "eslint"
+import rule from "../../../src/rules/valid-prop-names-in-kit-pages"
+import { loadTestCases } from "../../utils/utils"
+
+const tester = new RuleTester({
+  parserOptions: {
+    ecmaVersion: 2020,
+    sourceType: "module",
+  },
+})
+
+tester.run(
+  "valid-prop-names-in-kit-pages",
+  rule as any,
+  loadTestCases("valid-prop-names-in-kit-pages"),
+)