review

Author: liuxingbaoyu

src/rules/export.js

@@ -26,47 +26,25 @@ const rootProgram = 'root';
 const tsTypePrefix = 'type:';
 
 /**
- * Detect function overloads like:
+ * remove function overloads like:
  * ```ts
  * export function foo(a: number);
  * export function foo(a: string);
- * export function foo(a: number|string) { return a; }
  * ```
  * @param {Set<Object>} nodes
- * @returns {boolean}
  */
-function isTypescriptFunctionOverloads(nodes) {
-  const nodesArr = Array.from(nodes);
-
-  if (nodesArr[0].type === 'ExportDefaultDeclaration') {
-    let num = 0;
-    for (let i = 0; i < nodesArr.length; i++) {
-      const type = nodesArr[i].declaration.type;
-      if (
-        // eslint 6+
-        type === 'TSDeclareFunction'
-        // eslint 4-5
-        || type === 'TSEmptyBodyFunctionDeclaration'
-      ) {
-        num++;
-      }
+function removeTypescriptFunctionOverloads(nodes) {
+  nodes.forEach((node) => {
+    const declType = node.type === 'ExportDefaultDeclaration' ? node.declaration.type : node.parent.type;
+    if (
+      // eslint 6+
+      declType === 'TSDeclareFunction'
+      // eslint 4-5
+      || declType === 'TSEmptyBodyFunctionDeclaration'
+    ) {
+      nodes.delete(node);
     }
-    if (num === nodesArr.length - 1) {
-      return true;
-    }
-  }
-
-  const types = new Set(nodesArr.map((node) => node.parent.type));
-  if (!types.has('TSDeclareFunction')) {
-    return false;
-  }
-  if (types.size === 1) {
-    return true;
-  }
-  if (types.size === 2 && types.has('FunctionDeclaration')) {
-    return true;
-  }
-  return false;
+  });
 }
 
 /**
@@ -231,9 +209,11 @@ module.exports = {
       'Program:exit'() {
         for (const [, named] of namespace) {
           for (const [name, nodes] of named) {
+            removeTypescriptFunctionOverloads(nodes);
+
             if (nodes.size <= 1) { continue; }
 
-            if (isTypescriptFunctionOverloads(nodes) || isTypescriptNamespaceMerging(nodes)) { continue; }
+            if (isTypescriptNamespaceMerging(nodes)) { continue; }
 
             for (const node of nodes) {
               if (shouldSkipTypescriptNamespace(node, nodes)) { continue; }

tests/src/rules/export.js

@@ -163,6 +163,19 @@ ruleTester.run('export', rule, {
         ecmaVersion: 2022,
       },
     })),
+
+    getTSParsers().map((parser) => ({
+      code: `
+        export default function a(): void;
+        export default function a() {}
+        export { x as default };
+      `,
+      errors: [
+        'Multiple default exports.',
+        'Multiple default exports.',
+      ],
+      parser,
+    })),
   ),
 });
 
@@ -519,7 +532,7 @@ context('TypeScript', function () {
           }),
           test({
             code: `
-              export function Foo();
+              export function Foo() { };
               export class Foo { }
               export namespace Foo { }
             `,
@@ -538,7 +551,7 @@ context('TypeScript', function () {
           test({
             code: `
               export const Foo = 'bar';
-              export function Foo();
+              export function Foo() { };
               export namespace Foo { }
             `,
             errors: [