minor Array.from fixes

zloirock · Sep 18, 2021 · 9beeaad · 9beeaad
1 parent 7377472
commit 9beeaad
Showing 1 changed file with 5 additions and 5 deletions.
diff --git a/packages/core-js/internals/array-from.js b/packages/core-js/internals/array-from.js
@@ -13,26 +13,26 @@ var getIteratorMethod = require('../internals/get-iterator-method');
 // https://tc39.es/ecma262/#sec-array.from
 module.exports = function from(arrayLike /* , mapfn = undefined, thisArg = undefined */) {
   var O = toObject(arrayLike);
-  var C = isConstructor(this) ? this : Array;
+  var IS_CONSTRUCTOR = isConstructor(this);
   var argumentsLength = arguments.length;
   var mapfn = argumentsLength > 1 ? arguments[1] : undefined;
   var mapping = mapfn !== undefined;
+  if (mapping) mapfn = bind(mapfn, argumentsLength > 2 ? arguments[2] : undefined, 2);
   var iteratorMethod = getIteratorMethod(O);
   var index = 0;
   var length, result, step, iterator, next, value;
-  if (mapping) mapfn = bind(mapfn, argumentsLength > 2 ? arguments[2] : undefined, 2);
   // if the target is not iterable or it's an array with the default iterator - use a simple case
-  if (iteratorMethod && !(C == Array && isArrayIteratorMethod(iteratorMethod))) {
+  if (iteratorMethod && !(this == Array && isArrayIteratorMethod(iteratorMethod))) {
     iterator = getIterator(O, iteratorMethod);
     next = iterator.next;
-    result = new C();
+    result = IS_CONSTRUCTOR ? new this() : [];
     for (;!(step = next.call(iterator)).done; index++) {
       value = mapping ? callWithSafeIterationClosing(iterator, mapfn, [step.value, index], true) : step.value;
       createProperty(result, index, value);
     }
   } else {
     length = toLength(O.length);
-    result = new C(length);
+    result = IS_CONSTRUCTOR ? new this(length) : Array(length);
     for (;length > index; index++) {
       value = mapping ? mapfn(O[index], index) : O[index];
       createProperty(result, index, value);