js-on-sx: object literal __proto__ + try/catch error wrapping

lib/js/runtime.sx

@@ -991,6 +991,34 @@
 
 (define SuppressedError :js-undefined)
 
+(define
+  js-str-startswith?
+  (fn
+    (s prefix)
+    (cond
+      ((< (len s) (len prefix)) false)
+      (else (= (js-string-slice s 0 (len prefix)) prefix)))))
+
+(define
+  js-wrap-exn
+  (fn
+    (e)
+    (cond
+      ((not (= (type-of e) "string")) e)
+      ((js-str-startswith? e "Undefined symbol:")
+        (js-new-call ReferenceError (js-args e)))
+      ((js-str-startswith? e "TypeError:")
+        (js-new-call TypeError (js-args (js-string-slice e 11 (len e)))))
+      ((js-str-startswith? e "RangeError:")
+        (js-new-call RangeError (js-args (js-string-slice e 12 (len e)))))
+      ((js-str-startswith? e "SyntaxError:")
+        (js-new-call SyntaxError (js-args (js-string-slice e 13 (len e)))))
+      ((js-str-startswith? e "ReferenceError:")
+        (js-new-call ReferenceError (js-args (js-string-slice e 16 (len e)))))
+      ((js-str-startswith? e "URIError:")
+        (js-new-call URIError (js-args (js-string-slice e 10 (len e)))))
+      (else e))))
+
 (define
   js-date-from-one
   (fn
@@ -3194,7 +3222,12 @@
 
 (define
   js-make-obj
-  (fn () (let ((d (dict))) (begin (dict-set! d "__js_order__" (list)) d))))
+  (fn ()
+    (let ((d (dict)))
+      (begin
+        (dict-set! d "__js_order__" (list))
+        (dict-set! d "__proto__" (get Object "prototype"))
+        d))))
 
 (define
   js-obj-order-add!

lib/js/transpile.sx

@@ -1407,7 +1407,28 @@
     (let
       ((body-tr (js-transpile body)))
       (let
-        ((with-catch (cond ((= catch-part nil) body-tr) (else (let ((pname (nth catch-part 0)) (cbody (nth catch-part 1))) (list (js-sym "guard") (list (if (= pname nil) (js-sym "__exc__") (js-sym pname)) (list (js-sym "else") (js-transpile cbody))) body-tr))))))
+        ((with-catch
+           (cond
+             ((= catch-part nil) body-tr)
+             (else
+               (let
+                 ((pname (nth catch-part 0))
+                   (cbody (nth catch-part 1))
+                   (raw-sym (js-sym "__raw_exc__")))
+                 (list
+                   (js-sym "guard")
+                   (list
+                     raw-sym
+                     (list
+                       (js-sym "else")
+                       (cond
+                         ((= pname nil) (js-transpile cbody))
+                         (else
+                           (list
+                             (js-sym "let")
+                             (list (list (js-sym pname) (list (js-sym "js-wrap-exn") raw-sym)))
+                             (js-transpile cbody))))))
+                   body-tr))))))
         (cond
           ((= finally-part nil) with-catch)
           (else