fixup! lib: make safe primordials safe to iterate

nodejs · aduh95 · Dec 4, 2020 · Dec 5, 2020 · Dec 6, 2020 · Dec 6, 2020
commit 0e6ecc07e028630d30e34fd1cc9469b19bac9670
diff --git a/lib/internal/per_context/primordials.js b/lib/internal/per_context/primordials.js
@@ -72,19 +72,30 @@ function copyPrototype(src, dest, prefix) {
   }
 }
 
+const createSafeIterator = (factory, next) => {
+  class SafeIterator {
+    constructor(iterable) {
+      this._iterator = factory(iterable);
+    }
+    next() {
+      return next(this._iterator);
+    }
+  }
+  Object.setPrototypeOf(SafeIterator.prototype, null);
+  Object.freeze(SafeIterator.prototype);
+  Object.freeze(SafeIterator);
+  return function () {
+    return new SafeIterator(this);
+  };
+};
+
 function makeSafe(unsafe, safe) {
   copyProps(unsafe.prototype, safe.prototype);
   copyProps(unsafe, safe);
   if (Symbol.iterator in unsafe.prototype) {
     const createIterator = uncurryThis(unsafe.prototype[Symbol.iterator]);
-    const next = uncurryThis(
-      Reflect.getPrototypeOf(createIterator(new unsafe())).next
-    );
-    safe.prototype[Symbol.iterator] = function*() {
-      const iterator = createIterator(this);
-      let entry;
-      while (!(entry = next(iterator)).done) yield entry.value;
-    };
+    const next = uncurryThis(createIterator(new unsafe()).next);
+    safe.prototype[Symbol.iterator] = createSafeIterator(createIterator, next);
   }
   Object.setPrototypeOf(safe.prototype, null);
   Object.freeze(safe.prototype);