Perform lambda lifting for compile-time stuff when targeting JS. Enable unittest test.

compiler/lambdalifting.nim

@@ -946,7 +946,11 @@ proc transformOuterProc(o: POuterContext, n: PNode; it: TIter): PNode =
 proc liftLambdas*(fn: PSym, body: PNode): PNode =
   # XXX gCmd == cmdCompileToJS does not suffice! The compiletime stuff needs
   # the transformation even when compiling to JS ...
-  if body.kind == nkEmpty or gCmd == cmdCompileToJS or
+
+  # However we can do lifting for the stuff which is *only* compiletime.
+  let isCompileTime = sfCompileTime in fn.flags or fn.kind == skMacro
+
+  if body.kind == nkEmpty or (gCmd == cmdCompileToJS and not isCompileTime) or
       fn.skipGenericOwner.kind != skModule:
     # ignore forward declaration:
     result = body

lib/pure/unittest.nim

@@ -99,8 +99,9 @@ template test*(name: expr, body: stmt): stmt {.immediate, dirty.} =
       body
 
     except:
-      checkpoint("Unhandled exception: " & getCurrentExceptionMsg())
+      when not defined(js):
-      echo getCurrentException().getStackTrace()
+        checkpoint("Unhandled exception: " & getCurrentExceptionMsg())
+        echo getCurrentException().getStackTrace()
       fail()
 
     finally:
@@ -114,9 +115,7 @@ proc checkpoint*(msg: string) =
 template fail* =
   bind checkpoints
   for msg in items(checkpoints):
-    # this used to be 'echo' which now breaks due to a bug. XXX will revisit
+    echo msg
-    # this issue later.
-    stdout.writeln msg
 
   when not defined(ECMAScript):
     if abortOnError: quit(1)

tests/js/tunittests.nim

@@ -1,10 +1,7 @@
 discard """
-  disabled: "true"
+  output: '''[OK] >:)'''
 """
 
-# Unittest uses lambdalifting at compile-time which we disable for the JS
-# codegen! So this cannot and will not work for quite some time.
-
 import unittest
 
 suite "Bacon":