diff --git a/src/babel/util.js b/src/babel/util.js
index 45bbf2ce0d..373bfbb75c 100644
--- a/src/babel/util.js
+++ b/src/babel/util.js
@@ -55,7 +55,13 @@ export function resolveRelative(loc: string) {
 }
 
 export function list(val: string): Array<string> {
-  return val ? val.split(",") : [];
+  if (!val) {
+    return [];
+  } else if (Array.isArray(val)) {
+    return val;
+  } else {
+    return val.split(",");
+  }
 }
 
 export function regexify(val: any): RegExp {
diff --git a/test/core/util.js b/test/core/util.js
index 9f30ce1058..a26cc7f058 100644
--- a/test/core/util.js
+++ b/test/core/util.js
@@ -57,6 +57,7 @@ suite("util", function () {
     assert.deepEqual(util.list(""), []);
     assert.deepEqual(util.list("foo"), ["foo"]);
     assert.deepEqual(util.list("foo,bar"), ["foo", "bar"]);
+    assert.deepEqual(util.list(["foo", "bar"]), ["foo", "bar"]);
   });
 
   test("arrayify", function () {