Fix the classNames decorator declaration (#33)

#29

Author: ssutar

transforms/ember-object/__testfixtures__/decorators.output.js

@@ -8,7 +8,7 @@ import { on } from "@ember-decorators/object/evented";
 import templateLayout from "components/templates/foo";
 
 @tagName("div")
-@classNames(["test-class", "custom-class"])
+@classNames("test-class", "custom-class")
 class Foo extends EmberObject {
   a = "";
 

transforms/helpers/decorator-helper.js

@@ -21,10 +21,14 @@ function withDecorators(to, decorators = []) {
  * @returns {Decorator[]}
  */
 function createClassDecorator(j, classDecoratorProp) {
+  let decoratorArgs = [];
+  if (classDecoratorProp.type === "ArrayExpression") {
+    decoratorArgs = classDecoratorProp.value.elements;
+  } else {
+    decoratorArgs = [classDecoratorProp.value];
+  }
   return j.decorator(
-    j.callExpression(j.identifier(classDecoratorProp.key.name), [
-      classDecoratorProp.value
-    ])
+    j.callExpression(j.identifier(classDecoratorProp.name), [...decoratorArgs])
   );
 }