From d0cd7a39a2d05343c5501dc286bb59096659654f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E8=BF=B7=E6=B8=A1?= <justjavac@gmail.com>
Date: Fri, 19 Apr 2019 09:56:33 +0800
Subject: avoid prototype builtin hasOwnProperty (#2144)

---
 js/util.ts | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

(limited to 'js/util.ts')

diff --git a/js/util.ts b/js/util.ts
index e6f38c8e1..b81b96aca 100644
--- a/js/util.ts
+++ b/js/util.ts
@@ -142,3 +142,33 @@ export function getPrivateValue<
   }
   throw new TypeError("Illegal invocation");
 }
+
+/**
+ * Determines whether an object has a property with the specified name.
+ * Avoid calling prototype builtin `hasOwnProperty` for two reasons:
+ *
+ * 1. `hasOwnProperty` is defined on the object as something else:
+ *
+ *      const options = {
+ *        ending: 'utf8',
+ *        hasOwnProperty: 'foo'
+ *      };
+ *      options.hasOwnProperty('ending') // throws a TypeError
+ *
+ * 2. The object doesn't inherit from `Object.prototype`:
+ *
+ *       const options = Object.create(null);
+ *       options.ending = 'utf8';
+ *       options.hasOwnProperty('ending'); // throws a TypeError
+ *
+ * @param obj A Object.
+ * @param v A property name.
+ * @see https://eslint.org/docs/rules/no-prototype-builtins
+ * @internal
+ */
+export function hasOwnProperty<T>(obj: T, v: PropertyKey): boolean {
+  if (obj == null) {
+    return false;
+  }
+  return Object.prototype.hasOwnProperty.call(obj, v);
+}
-- 
cgit v1.2.3