Reviewers: arv, Dmitry S. Lomov, rossberg,
Message:
PTAL, quick fixup following allen's comment on
https://esdiscuss.org/topic/isconcatspreadable
Description:
[es6] fix IsConcatSpreadable() algorithm in runtime-array.cc
The ordering of the "IsArray()" check for IsConcatSpreadable() either
moved, or
was
just wrong before. IsArray() is used if Get(O, @@isConcatSpreadable) is
undefined.
22.1.3.1.1
https://people.mozilla.org/~jorendorff/es6-draft.html#sec-isconcatspreadable
BUG=v8:3764
LOG=N
[email protected], [email protected], [email protected]
Please review this at https://codereview.chromium.org/1192153002/
Base URL: https://chromium.googlesource.com/v8/v8.git@master
Affected files (+26, -3 lines):
M src/runtime/runtime-array.cc
M test/mjsunit/harmony/array-concat.js
Index: src/runtime/runtime-array.cc
diff --git a/src/runtime/runtime-array.cc b/src/runtime/runtime-array.cc
index
c468673dd5298f472a91d1a89edbdbf7ba4d2877..806af12b55b3631e9818d1af24a9e5746ae0d118
100644
--- a/src/runtime/runtime-array.cc
+++ b/src/runtime/runtime-array.cc
@@ -724,17 +724,18 @@ static bool IterateElements(Isolate* isolate,
Handle<JSObject> receiver,
static bool IsConcatSpreadable(Isolate* isolate, Handle<Object> obj) {
HandleScope handle_scope(isolate);
if (!obj->IsSpecObject()) return false;
- if (obj->IsJSArray()) return true;
if (FLAG_harmony_arrays) {
Handle<Symbol> key(isolate->factory()->is_concat_spreadable_symbol());
Handle<Object> value;
MaybeHandle<Object> maybeValue =
i::Runtime::GetObjectProperty(isolate, obj, key);
if (maybeValue.ToHandle(&value)) {
- return value->BooleanValue();
+ if (!value->IsUndefined()) {
+ return value->BooleanValue();
+ }
}
}
- return false;
+ return obj->IsJSArray();
}
Index: test/mjsunit/harmony/array-concat.js
diff --git a/test/mjsunit/harmony/array-concat.js
b/test/mjsunit/harmony/array-concat.js
index
c1ff92c8c3df03100571eafb0f91dd2ad1abbcec..b623a5cc114303a50a39f25e39bb40a6053e1459
100644
--- a/test/mjsunit/harmony/array-concat.js
+++ b/test/mjsunit/harmony/array-concat.js
@@ -194,6 +194,15 @@ assertThrows(function() {
(function testConcatArraySubclass() {
"use strict";
+ // If @@isConcatSpreadable is not used, the value of IsArray(O)
+ // is used to determine the spreadable property.
+ class A extends Array {}
+ var obj = [].concat(new A(1, 2, 3), new A(4, 5, 6), new A(7, 8, 9));
+ assertEquals(9, obj.length);
+ for (var i = 0; i < obj.length; ++i) {
+ assertEquals(i + 1, obj[i]);
+ }
+
// TODO(caitp): when concat is called on instances of classes which
extend
// Array, they should:
//
@@ -203,6 +212,19 @@ assertThrows(function() {
})();
+(function testConcatArraySubclassOptOut() {
+ "use strict";
+ class A extends Array {
+ get [Symbol.isConcatSpreadable]() { return false; }
+ }
+ var obj = [].concat(new A(1, 2, 3), new A(4, 5, 6), new A(7, 8, 9));
+ assertEquals(3, obj.length);
+ assertEquals(3, obj[0].length);
+ assertEquals(3, obj[1].length);
+ assertEquals(3, obj[2].length);
+})();
+
+
(function testConcatNonArray() {
"use strict";
class NonArray {
--
--
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