From 8eed600d5b2be78c405f7ef139a7b0e4a2480c85 Mon Sep 17 00:00:00 2001
From: James Ide <ide@jameside.com>
Date: Mon, 15 Aug 2016 10:37:29 -0700
Subject: [PATCH] Define Flow types for style and stylesheet objects, more
 checking

Summary:
- Define a Styles type for the object that gets passed into StyleSheet.create
- Define a StyleSheet type that is returned from StyleSheet.create
- Clean up the type declarations in StyleSheet.create
Closes https://github.com/facebook/react-native/pull/8882

Differential Revision: D3587964

Pulled By: gabelevi

fbshipit-source-id: 629e0176484436848be69b1417638e1200a3669a
---
 Libraries/StyleSheet/StyleSheet.js | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/Libraries/StyleSheet/StyleSheet.js b/Libraries/StyleSheet/StyleSheet.js
index c9eab42c4bb..e4f767f9e15 100644
--- a/Libraries/StyleSheet/StyleSheet.js
+++ b/Libraries/StyleSheet/StyleSheet.js
@@ -17,6 +17,9 @@ var StyleSheetValidation = require('StyleSheetValidation');
 
 var flatten = require('flattenStyle');
 
+export type Styles = {[key: string]: Object};
+export type StyleSheet<S: Styles> = {[key: $Keys<S>]: number};
+
 var hairlineWidth = PixelRatio.roundToNearestPixel(0.4);
 if (hairlineWidth === 0) {
   hairlineWidth = 1 / PixelRatio.get();
@@ -160,8 +163,8 @@ module.exports = {
   /**
    * Creates a StyleSheet style reference from the given object.
    */
-  create<T: Object, U>(obj: T): {[key:$Keys<T>]: number} {
-    var result: T = (({}: any): T);
+  create<S: Styles>(obj: S): StyleSheet<S> {
+    const result: StyleSheet<S> = {};
     for (var key in obj) {
       StyleSheetValidation.validateStyle(key, obj);
       result[key] = ReactNativePropRegistry.register(obj[key]);