made nodecl implicit for vars in the js backend. (#5297)

compiler/jsgen.nim

@@ -1528,7 +1528,7 @@ proc genVarStmt(p: PProc, n: PNode) =
         assert(a.kind == nkIdentDefs)
         assert(a.sons[0].kind == nkSym)
         var v = a.sons[0].sym
-        if lfNoDecl notin v.loc.flags:
+        if lfNoDecl notin v.loc.flags and sfImportc notin v.flags:
           genLineDir(p, a)
           genVarInit(p, v, a.sons[2])
 

tests/js/timplicit_nodecl.nim

@@ -0,0 +1,13 @@
+discard """
+  output: '''22
+22'''
+"""
+
+# test implicit nodecl
+block:
+  {. emit: "var importMe = 22;" .}
+  var
+    a {. importc: "importMe" .}: int
+    importMe {. importc .}: int
+  echo a
+  echo importMe

tests/js/tvarargs.nim

@@ -6,7 +6,7 @@ type
     log*: proc() {.nimcall varargs.}
   Console = ref ConsoleObj
 
-var console* {.importc nodecl.}: Console
+var console* {.importc.}: Console
 
 when isMainModule:
   console.log "Hello, world"