diff --git a/local-cli/util/Config.js b/local-cli/util/Config.js
index 987046bae..5454e2121 100644
--- a/local-cli/util/Config.js
+++ b/local-cli/util/Config.js
@@ -21,6 +21,7 @@ const RN_CLI_CONFIG = 'rn-cli.config.js';
 
 import type {GetTransformOptions, PostMinifyProcess, PostProcessModules} from '../../packager/src/Bundler';
 import type {HasteImpl} from '../../packager/src/node-haste/Module';
+import type {TransformVariants} from '../../packager/src/ModuleGraph/types.flow';
 
 /**
  * Configuration file of the CLI.
@@ -89,7 +90,7 @@ export type ConfigT = {
    */
   hasteImpl?: HasteImpl,
 
-  transformVariants: () => {[name: string]: Object},
+  transformVariants: () => TransformVariants,
 };
 
 const defaultConfig: ConfigT = {
diff --git a/packager/src/ModuleGraph/types.flow.js b/packager/src/ModuleGraph/types.flow.js
index dd1056302..4070f27c3 100644
--- a/packager/src/ModuleGraph/types.flow.js
+++ b/packager/src/ModuleGraph/types.flow.js
@@ -123,7 +123,7 @@ export type TransformResult = {|
 
 export type TransformResults = {[string]: TransformResult};
 
-export type TransformVariants = {[key: string]: Object};
+export type TransformVariants = {+[name: string]: {}, +default: {}};
 
 export type TransformedCodeFile = {
   +code: string,