Export classes from type definition (axios#5031)

index.js

@@ -1,2 +1,4 @@
 import axios from './lib/axios.js';
+
+export * from './lib/axios.js';
 export default axios;

test/unit/regression/bugs.js

@@ -1,5 +1,5 @@
 import assert from 'assert';
-import axios from '../../../index.js';
+import axios, { AxiosError, AxiosHeaders, Axios, CanceledError } from '../../../index.js';
 
 describe('issues', function () {
   describe('4999', function () {
@@ -10,4 +10,22 @@ describe('issues', function () {
       assert.strictEqual(data.args.foo2, 'bar2');
     });
   });
+
+  describe('5031', function () {
+    it('should export class AxiosHeaders', async function () {
+      assert.doesNotThrow(() => new AxiosHeaders(), 'class AxiosHeaders not exported');
+    });
+
+    it('should export class Axios', async function () {
+      assert.doesNotThrow(() => new Axios(), 'class Axios not exported');
+    });
+
+    it('should export class AxiosError', async function () {
+      assert.doesNotThrow(() => new AxiosError('Error'), 'class AxiosError not exported');
+    });
+
+    it('should export class CanceledError', async function () {
+      assert.doesNotThrow(() => new CanceledError('Message'), 'class CanceledError not exported');
+    });
+  });
 });