close #18129 Add setCurrentException for JS backend (#18145)

* [std/re] make interface consistent

* tiny

* revert

* close #18129  add setCurrentException

* changelog entry

changelog.md

@@ -329,7 +329,7 @@
 
 - Fixed premature garbage collection in asyncdispatch, when a stack trace override is in place.
 
-
+- Added setCurrentException for JS backend.
 
 ## Language changes
 

lib/system/jssys.nim

@@ -69,6 +69,9 @@ proc getCurrentExceptionMsg*(): string =
         return $msg
   return ""
 
+proc setCurrentException*(exc: ref Exception) =
+  lastJSError = cast[PJSError](exc)
+
 proc auxWriteStackTrace(f: PCallFrame): string =
   type
     TempFrame = tuple[procname: cstring, line: int, filename: cstring]

tests/exception/tsetexceptions.nim

@@ -0,0 +1,8 @@
+discard """
+  targets: "c cpp js"
+"""
+
+let ex = newException(CatchableError, "test")
+setCurrentException(ex)
+doAssert getCurrentException().msg == ex.msg
+doAssert getCurrentExceptionMsg() == ex.msg