fix

Author: liuxingbaoyu

src/rules/export.js

@@ -2,7 +2,6 @@ import ExportMapBuilder from '../exportMap/builder';
 import recursivePatternCapture from '../exportMap/patternCapture';
 import docsUrl from '../docsUrl';
 import includes from 'array-includes';
-import flatMap from 'array.prototype.flatmap';
 
 /*
 Notes on TypeScript namespaces aka TSModuleDeclaration:
@@ -39,17 +38,21 @@ const tsTypePrefix = 'type:';
 function isTypescriptFunctionOverloads(nodes) {
   const nodesArr = Array.from(nodes);
 
-  const idents = flatMap(
-    nodesArr,
-    (node) => node.declaration && (
-      node.declaration.type === 'TSDeclareFunction' // eslint 6+
-      || node.declaration.type === 'TSEmptyBodyFunctionDeclaration' // eslint 4-5
-    )
-      ? node.declaration.id.name
-      : [],
-  );
-  if (new Set(idents).size !== idents.length) {
-    return true;
+  if (nodesArr[0].type === 'ExportDefaultDeclaration') {
+    let num = 0;
+    for (const node of nodesArr) {
+      if (
+        // eslint 6+
+        node.declaration.type === 'TSDeclareFunction'
+        // eslint 4-5
+        || node.declaration.type === 'TSEmptyBodyFunctionDeclaration'
+      ) {
+        num++;
+      }
+    }
+    if (num === nodesArr.length - 1) {
+      return true;
+    }
   }
 
   const types = new Set(nodesArr.map((node) => node.parent.type));

tests/src/rules/export.js

@@ -56,6 +56,15 @@ ruleTester.run('export', rule, {
       `,
       parser,
     })),
+    getTSParsers().map((parser) => ({
+      code: `
+        export default function foo(param: string): boolean;
+        export default function foo(param: string, param1?: number): boolean {
+          return param && param1;
+        }
+      `,
+      parser,
+    })),
   ),
 
   invalid: [].concat(