js-on-sx: JSON.parse raises SyntaxError, rejects trailing content + control chars

lib/js/runtime.sx

@@ -5321,12 +5321,21 @@
     (&rest args)
     (if
       (= (len args) 0)
-      js-undefined
+      (raise (js-new-call SyntaxError (js-args "Unexpected token undefined")))
       (let
         ((st (dict)))
         (dict-set! st "s" (js-to-string (nth args 0)))
         (dict-set! st "i" 0)
-        (js-json-parse-value st)))))
+        (let
+          ((result (js-json-parse-value st)))
+          (begin
+            (js-json-skip-ws! st)
+            (if
+              (< (get st "i") (len (get st "s")))
+              (raise
+                (js-new-call SyntaxError
+                  (js-args (str "Unexpected token at position " (get st "i")))))
+              result)))))))
 
 (define
   js-json-skip-ws!
@@ -5348,7 +5357,7 @@
     (let
       ((s (get st "s")) (i (get st "i")))
       (cond
-        ((>= i (len s)) (error "JSON: unexpected end"))
+        ((>= i (len s)) (raise (js-new-call SyntaxError (js-args "JSON: unexpected end"))))
         ((= (char-at s i) "\"") (js-json-parse-string st))
         ((= (char-at s i) "[") (js-json-parse-array st))
         ((= (char-at s i) "{") (js-json-parse-object st))
@@ -5380,8 +5389,13 @@
     (let
       ((i (get st "i")))
       (cond
-        ((>= i (len s)) nil)
+        ((>= i (len s))
+          (raise (js-new-call SyntaxError (js-args "JSON: unterminated string"))))
         ((= (char-at s i) "\"") nil)
+        ((< (char-code (char-at s i)) 32)
+          (raise
+            (js-new-call SyntaxError
+              (js-args "JSON: control character in string"))))
         ((= (char-at s i) "\\")
           (begin
             (when
@@ -5457,7 +5471,7 @@
             (js-json-skip-ws! st)
             (js-json-parse-array-loop st result)))
         ((= c "]") (dict-set! st "i" (+ (get st "i") 1)))
-        (else (error "JSON: expected , or ]"))))))
+        (else (raise (js-new-call SyntaxError (js-args "JSON: expected , or ]"))))))))
 
 (define
   js-json-parse-object
@@ -5482,7 +5496,7 @@
       (js-json-skip-ws! st)
       (when
         (not (= (char-at (get st "s") (get st "i")) ":"))
-        (error "JSON: expected :"))
+        (raise (js-new-call SyntaxError (js-args "JSON: expected :"))))
       (dict-set! st "i" (+ (get st "i") 1))
       (let ((v (js-json-parse-value st))) (dict-set! result k v))
       (js-json-skip-ws! st)
@@ -5494,7 +5508,7 @@
               (dict-set! st "i" (+ (get st "i") 1))
               (js-json-parse-object-loop st result)))
           ((= c "}") (dict-set! st "i" (+ (get st "i") 1)))
-          (else (error "JSON: expected , or }")))))))
+          (else (raise (js-new-call SyntaxError (js-args "JSON: expected , or }")))))))))
 
 (define JSON {:stringify js-json-stringify :parse js-json-parse})