chore(core): remove the isomorphic-unfetch dependency (#12023)

packages/core/__tests__/clients/fetch.test.ts

@@ -1,8 +1,3 @@
-const mockUnfetch = jest.fn();
-jest.mock('isomorphic-unfetch', () => {
-	global['fetch'] = mockUnfetch;
-});
-
 import { fetchTransferHandler } from '../../src/clients/handlers/fetch';
 
 describe(fetchTransferHandler.name, () => {
@@ -25,17 +20,22 @@ describe(fetchTransferHandler.name, () => {
 		url: new URL('https://foo.bar'),
 	};
 	const mockPayloadValue = 'payload value';
+	const mockFetch = jest.fn();
+
+	beforeAll(() => {
+		global['fetch'] = mockFetch;
+	});
 
 	beforeEach(() => {
 		jest.clearAllMocks();
-		mockUnfetch.mockResolvedValue(mockFetchResponse);
+		mockFetch.mockResolvedValue(mockFetchResponse);
 	});
 
 	test('should support abort signal', async () => {
 		const signal = new AbortController().signal;
 		await fetchTransferHandler(mockRequest, { abortSignal: signal });
-		expect(mockUnfetch).toBeCalledTimes(1);
-		expect(mockUnfetch.mock.calls[0][1]).toEqual(
+		expect(mockFetch).toBeCalledTimes(1);
+		expect(mockFetch.mock.calls[0][1]).toEqual(
 			expect.objectContaining({ signal })
 		);
 	});
@@ -88,8 +88,8 @@ describe(fetchTransferHandler.name, () => {
 				{ ...mockRequest, method, body: 'Mock Body' },
 				{}
 			);
-			expect(mockUnfetch).toBeCalledTimes(1);
-			expect(mockUnfetch.mock.calls[0][0].body).toBeUndefined();
+			expect(mockFetch).toBeCalledTimes(1);
+			expect(mockFetch.mock.calls[0][0].body).toBeUndefined();
 		}
 	);
 });

packages/core/package.json

@@ -65,8 +65,6 @@
 		"@aws-crypto/sha256-js": "5.0.0",
 		"@aws-sdk/types": "3.398.0",
 		"@smithy/util-hex-encoding": "2.0.0",
-		"@types/node-fetch": "2.6.4",
-		"isomorphic-unfetch": "^3.0.0",
 		"tslib": "^2.5.0",
 		"uuid": "^9.0.0",
 		"zen-observable-ts": "0.8.19",

packages/core/src/clients/handlers/fetch.ts

@@ -1,7 +1,6 @@
 // Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
-import 'isomorphic-unfetch'; // TODO: remove this dependency in v6
 import { HttpRequest, HttpResponse, HttpTransferOptions } from '../types/http';
 import { TransferHandler } from '../types/core';
 import { withMemoization } from '../utils/memoization';