Fixes #71993: Ensure Buffer is always used when available

src/vs/base/common/buffer.ts

@@ -4,7 +4,7 @@
  *--------------------------------------------------------------------------------------------*/
 
 declare var Buffer: any;
-const hasBuffer = (typeof Buffer !== 'undefined');
+export const hasBuffer = (typeof Buffer !== 'undefined');
 
 let textEncoder: TextEncoder | null;
 let textDecoder: TextDecoder | null;
@@ -20,6 +20,11 @@ export class VSBuffer {
 	}
 
 	public static wrap(actual: Uint8Array): VSBuffer {
+		if (hasBuffer && !(Buffer.isBuffer(actual))) {
+			// https://nodejs.org/dist/latest-v10.x/docs/api/buffer.html#buffer_class_method_buffer_from_arraybuffer_byteoffset_length
+			// Create a zero-copy Buffer wrapper around the ArrayBuffer pointed to by the Uint8Array
+			actual = Buffer.from(actual.buffer, actual.byteOffset, actual.byteLength);
+		}
 		return new VSBuffer(actual);
 	}
 

src/vs/base/test/common/buffer.test.ts

+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+
+import * as assert from 'assert';
+import { hasBuffer, VSBuffer } from 'vs/base/common/buffer';
+
+suite('Buffer', () => {
+
+	if (hasBuffer) {
+		test('issue #71993 - VSBuffer#toString returns numbers', () => {
+			const data = new Uint8Array([1, 2, 3, 'h'.charCodeAt(0), 'i'.charCodeAt(0), 4, 5]).buffer;
+			const buffer = VSBuffer.wrap(new Uint8Array(data, 3, 2));
+			assert.deepEqual(buffer.toString(), 'hi');
+		});
+	}
+
+});