Issue #2256 - Implement Object.hasOwn(object, property)

This is a convenience access function to hasOwnProperty.

Trivial, self-hosted implementation providing the interface to the
already existing hasOwnProperty cpp function with additional toObject
for spec compliance.

Resolves #2256

2 files changed, 10 insertions, 0 deletions

diff --git a/js/src/builtin/Object.cpp b/js/src/builtin/Object.cpp
index 70a21079c0..5221afb617 100644
--- a/js/src/builtin/Object.cpp
+++ b/js/src/builtin/Object.cpp
@@ -1240,6 +1240,7 @@ static const JSFunctionSpec object_static_methods[] = {
     JS_FN("seal",                      obj_seal,                    1, 0),
     JS_FN("isSealed",                  obj_isSealed,                1, 0),
     JS_SELF_HOSTED_FN("fromEntries",   "ObjectFromEntries",         1, 0),
+    JS_SELF_HOSTED_FN("hasOwn",        "ObjectHasOwn",              2, 0),
     JS_FS_END
 };
 
diff --git a/js/src/builtin/Object.js b/js/src/builtin/Object.js
index c4739037e3..59d4807317 100644
--- a/js/src/builtin/Object.js
+++ b/js/src/builtin/Object.js
@@ -220,3 +220,12 @@ function ObjectFromEntries(iter) {
 
     return obj;
 }
+
+// Proposal https://github.com/tc39/proposal-accessible-object-hasownproperty
+// Object.hasOwn (Object, Property)
+function ObjectHasOwn(O, P) {
+    // Step 1.
+    var obj = ToObject(O);
+    // Step 2-3.
+    return callFunction(std_Object_hasOwnProperty, obj, P);
+}