From 1fbd24855f90db4028bfa3244cfb2eb50d499883 Mon Sep 17 00:00:00 2001
From: Evan Jacobs <probablyup@gmail.com>
Date: Mon, 24 Jun 2019 20:14:12 -0500
Subject: [PATCH] revise & simplify theme determination

---
 packages/styled-components/src/utils/determineTheme.js | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/packages/styled-components/src/utils/determineTheme.js b/packages/styled-components/src/utils/determineTheme.js
index 5f3afff3..5d242cf5 100644
--- a/packages/styled-components/src/utils/determineTheme.js
+++ b/packages/styled-components/src/utils/determineTheme.js
@@ -5,11 +5,6 @@ type Props = {
   theme?: any,
 };
 
-export default (props: Props, fallbackTheme: any, defaultProps: any = EMPTY_OBJECT) => {
-  // Props should take precedence over ThemeProvider, which should take precedence over
-  // defaultProps, but React automatically puts defaultProps on props.
-  const isDefaultTheme = defaultProps ? props.theme === defaultProps.theme : false;
-  const theme = props.theme && !isDefaultTheme ? props.theme : fallbackTheme || defaultProps.theme;
-
-  return theme;
+export default (props: Props, providedTheme: any, defaultProps: any = EMPTY_OBJECT) => {
+  return (props.theme !== defaultProps.theme && props.theme) || providedTheme || defaultProps.theme;
 };