False positives for type-only exports in vue/no-export-in-script-setup rule

Author: ota-meshi

lib/rules/no-export-in-script-setup.js

@@ -6,6 +6,12 @@
 
 const utils = require('../utils')
 
+/**
+ * @typedef {import('@typescript-eslint/types').TSESTree.ExportAllDeclaration} TSESTreeExportAllDeclaration
+ * @typedef {import('@typescript-eslint/types').TSESTree.ExportDefaultDeclaration} TSESTreeExportDefaultDeclaration
+ * @typedef {import('@typescript-eslint/types').TSESTree.ExportNamedDeclaration} TSESTreeExportNamedDeclaration
+ */
+
 module.exports = {
   meta: {
     type: 'problem',
@@ -23,17 +29,32 @@ module.exports = {
   /** @param {RuleContext} context */
   create(context) {
     /** @param {ExportAllDeclaration | ExportDefaultDeclaration | ExportNamedDeclaration} node */
-    function report(node) {
+    function verify(node) {
+      const tsNode =
+        /** @type {TSESTreeExportAllDeclaration | TSESTreeExportDefaultDeclaration | TSESTreeExportNamedDeclaration} */ (
+          node
+        )
+      if (tsNode.exportKind === 'type') {
+        return
+      }
+      if (tsNode.type === 'ExportNamedDeclaration') {
+        if (
+          tsNode.specifiers.length > 0 &&
+          tsNode.specifiers.every((spec) => spec.exportKind === 'type')
+        ) {
+          return
+        }
+      }
       context.report({
         node,
         messageId: 'forbidden'
       })
     }
 
     return utils.defineScriptSetupVisitor(context, {
-      ExportAllDeclaration: report,
-      ExportDefaultDeclaration: report,
-      ExportNamedDeclaration: report
+      ExportAllDeclaration: verify,
+      ExportDefaultDeclaration: verify,
+      ExportNamedDeclaration: verify
     })
   }
 }

package.json

@@ -65,7 +65,7 @@
     "@types/natural-compare": "^1.4.0",
     "@types/node": "^13.13.5",
     "@types/semver": "^7.2.0",
-    "@typescript-eslint/parser": "^5.0.0-0",
+    "@typescript-eslint/parser": "^5.4.0",
     "@vuepress/plugin-pwa": "^1.4.1",
     "acorn": "^8.5.0",
     "env-cmd": "^10.1.0",
@@ -82,7 +82,7 @@
     "mocha": "^7.1.2",
     "nyc": "^15.1.0",
     "prettier": "^2.4.1",
-    "typescript": "^4.4.3",
+    "typescript": "^4.5.0-0",
     "vue-eslint-editor": "^1.1.0",
     "vuepress": "^1.8.2"
   }

tests/lib/rules/no-export-in-script-setup.js

@@ -8,6 +8,7 @@
 // Requirements
 // ------------------------------------------------------------------------------
 
+const semver = require('semver')
 const eslint = require('eslint')
 const rule = require('../../../lib/rules/no-export-in-script-setup')
 
@@ -48,7 +49,43 @@ ruleTester.run('no-export-in-script-setup', rule, {
       let foo;
       </script>
       `
-    }
+    },
+    ...(semver.gte(
+      require('@typescript-eslint/parser/package.json').version,
+      '5.4.0'
+    ) &&
+    semver.satisfies(require('typescript/package.json').version, '>=4.5.0-0')
+      ? [
+          {
+            filename: 'test.vue',
+            code: `
+            <script setup lang="ts">
+            export { type Foo } from "foo"
+            export type Bar = {}
+            export interface Bar {}
+            </script>
+            `,
+            parser: require.resolve('vue-eslint-parser'),
+            parserOptions: {
+              parser: require.resolve('@typescript-eslint/parser')
+            }
+          }
+        ]
+      : [
+          {
+            filename: 'test.vue',
+            code: `
+            <script setup lang="ts">
+            export type Bar = {}
+            export interface Bar {}
+            </script>
+            `,
+            parser: require.resolve('vue-eslint-parser'),
+            parserOptions: {
+              parser: require.resolve('@typescript-eslint/parser')
+            }
+          }
+        ])
   ],
 
   invalid: [
@@ -102,6 +139,34 @@ ruleTester.run('no-export-in-script-setup', rule, {
           line: 8
         }
       ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script setup lang="ts">
+      export const Foo = {}
+      export enum Bar {}
+      export {}
+      </script>
+      `,
+      parser: require.resolve('vue-eslint-parser'),
+      parserOptions: {
+        parser: require.resolve('@typescript-eslint/parser')
+      },
+      errors: [
+        {
+          message: '`<script setup>` cannot contain ES module exports.',
+          line: 3
+        },
+        {
+          message: '`<script setup>` cannot contain ES module exports.',
+          line: 4
+        },
+        {
+          message: '`<script setup>` cannot contain ES module exports.',
+          line: 5
+        }
+      ]
     }
   ]
 })