buffer: fix check for .buffer property

isSharedArrayBuffer in fromObject was missing obj.buffer moved the 'length' in obj check so that it is checked first making the code slightly more performant and able to handle SharedArrayBuffer without relying on an explicit check. Ref: #8510 PR-URL: #8739 Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com> Reviewed-By: Anna Henningsen <anna@addaleax.net>
nodejs · Oct 11, 2016 · 5c10898 · 5c10898
1 parent b579fca
commit 5c10898
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Showing 2 changed files with 4 additions and 2 deletions.
diff --git a/lib/buffer.js b/lib/buffer.js
@@ -246,8 +246,8 @@ function fromObject(obj) {
   }
 
   if (obj) {
-    if (isArrayBuffer(obj.buffer) || 'length' in obj ||
-        isSharedArrayBuffer(obj)) {
+    if ('length' in obj || isArrayBuffer(obj.buffer) ||
+        isSharedArrayBuffer(obj.buffer)) {
       if (typeof obj.length !== 'number' || obj.length !== obj.length) {
         return new FastBuffer();
       }

diff --git a/test/parallel/test-buffer-sharedarraybuffer.js b/test/parallel/test-buffer-sharedarraybuffer.js
@@ -27,3 +27,5 @@ assert.deepStrictEqual(arr_buf, ar_buf, 0);
 // Checks for calling Buffer.byteLength on a SharedArrayBuffer
 
 assert.strictEqual(Buffer.byteLength(sab), sab.byteLength, 0);
+
+assert.doesNotThrow(() => Buffer.from({buffer: sab}));
Original file line number	Diff line number	Diff line change
Expand Up		@@ -27,3 +27,5 @@ assert.deepStrictEqual(arr_buf, ar_buf, 0);
		// Checks for calling Buffer.byteLength on a SharedArrayBuffer

		assert.strictEqual(Buffer.byteLength(sab), sab.byteLength, 0);

		assert.doesNotThrow(() => Buffer.from({buffer: sab}));