buffer: add @@toStringTag to Blob

This commit adds the toStringTag to the Blob class to match
the behavior of Chrome and Firefox.

PR-URL: #37336
Backport-PR-URL: #39704
Fixes: #37337
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Antoine du Hamel <[email protected]>
Reviewed-By: James M Snell <[email protected]>

Author: cjihrig

lib/internal/blob.js

@@ -2,12 +2,14 @@
 
 const {
   ArrayFrom,
+  ObjectDefineProperty,
   ObjectSetPrototypeOf,
   PromiseResolve,
   RegExpPrototypeTest,
   StringPrototypeToLowerCase,
   Symbol,
   SymbolIterator,
+  SymbolToStringTag,
   Uint8Array,
 } = primordials;
 
@@ -219,6 +221,11 @@ class Blob extends JSTransferable {
   }
 }
 
+ObjectDefineProperty(Blob.prototype, SymbolToStringTag, {
+  configurable: true,
+  value: 'Blob',
+});
+
 InternalBlob.prototype.constructor = Blob;
 ObjectSetPrototypeOf(
   InternalBlob.prototype,

test/parallel/test-blob.js

@@ -185,3 +185,14 @@ assert.throws(() => new Blob(['test', 1]), {
   const b = new Blob(['hello'], { type: '\x01' });
   assert.strictEqual(b.type, '');
 }
+
+{
+  const descriptor =
+      Object.getOwnPropertyDescriptor(Blob.prototype, Symbol.toStringTag);
+  assert.deepStrictEqual(descriptor, {
+    configurable: true,
+    enumerable: false,
+    value: 'Blob',
+    writable: false
+  });
+}