js-on-sx: Error.isError + [[ErrorData]] slot + verifyEqualTo

lib/js/runtime.sx

@@ -834,10 +834,36 @@
                 (= (len args) 0)
                 ""
                 (js-to-string (nth args 0))))
-            (dict-set! this "name" "Error"))
+            (dict-set! this "name" "Error")
+            (dict-set! this "__js_error_data__" true))
           nil)
         this))))
 
+(define
+  js-error-is-error
+  (fn
+    (&rest args)
+    (cond
+      ((= (len args) 0) false)
+      (else
+        (let
+          ((v (nth args 0)))
+          (and
+            (= (type-of v) "dict")
+            (or
+              (contains? (keys v) "__js_error_data__")
+              (js-error-proto-walk? v))))))))
+
+(define
+  js-error-proto-walk?
+  (fn
+    (v)
+    (cond
+      ((not (= (type-of v) "dict")) false)
+      ((contains? (keys v) "__js_error_data__") true)
+      ((not (contains? (keys v) "__proto__")) false)
+      (else (js-error-proto-walk? (get v "__proto__"))))))
+
 ;; ── Math object ───────────────────────────────────────────────────
 
 (define
@@ -857,7 +883,8 @@
                 (= (len args) 0)
                 ""
                 (js-to-string (nth args 0))))
-            (dict-set! this "name" "TypeError"))
+            (dict-set! this "name" "TypeError")
+            (dict-set! this "__js_error_data__" true))
           nil)
         this))))
 (define
@@ -877,7 +904,8 @@
                 (= (len args) 0)
                 ""
                 (js-to-string (nth args 0))))
-            (dict-set! this "name" "RangeError"))
+            (dict-set! this "name" "RangeError")
+            (dict-set! this "__js_error_data__" true))
           nil)
         this))))
 (define
@@ -897,7 +925,8 @@
                 (= (len args) 0)
                 ""
                 (js-to-string (nth args 0))))
-            (dict-set! this "name" "SyntaxError"))
+            (dict-set! this "name" "SyntaxError")
+            (dict-set! this "__js_error_data__" true))
           nil)
         this))))
 (define
@@ -917,7 +946,8 @@
                 (= (len args) 0)
                 ""
                 (js-to-string (nth args 0))))
-            (dict-set! this "name" "ReferenceError"))
+            (dict-set! this "name" "ReferenceError")
+            (dict-set! this "__js_error_data__" true))
           nil)
         this))))
 (define
@@ -935,7 +965,8 @@
               this
               "message"
               (if (empty? args) "" (js-to-string (nth args 0))))
-            (dict-set! this "name" "URIError")))
+            (dict-set! this "name" "URIError")
+            (dict-set! this "__js_error_data__" true)))
         this))))
 (define
   EvalError
@@ -952,8 +983,13 @@
               this
               "message"
               (if (empty? args) "" (js-to-string (nth args 0))))
-            (dict-set! this "name" "EvalError")))
+            (dict-set! this "name" "EvalError")
+            (dict-set! this "__js_error_data__" true)))
         this))))
+
+(define AggregateError :js-undefined)
+
+(define SuppressedError :js-undefined)
 (define
   js-function?
   (fn
@@ -2965,6 +3001,8 @@
           (js-dict-get-walk obj (js-to-string key)))
         ((and (= obj Promise) (dict-has? __js_promise_statics__ (js-to-string key)))
           (get __js_promise_statics__ (js-to-string key)))
+        ((and (= obj Error) (= (js-to-string key) "isError"))
+          js-error-is-error)
         ((and (js-function? obj) (or (= key "prototype") (= key "name") (= key "length") (= key "call") (= key "apply") (= key "bind") (= key "constructor")))
           (cond
             ((= key "prototype") (js-get-ctor-proto obj))

lib/js/test262-runner.py

@@ -134,6 +134,9 @@ var verifyProperty = function (obj, name, desc, opts) {
   }
 };
 var verifyPrimordialProperty = verifyProperty;
+var verifyEqualTo = function (obj, name, value) {
+  assert.sameValue(obj[name], value, name + " equals");
+};
 var verifyNotEnumerable = function (o, n, v, w, x) { };
 var verifyNotWritable = function (o, n, v, w, x) { };
 var verifyNotConfigurable = function (o, n, v, w, x) { };