give canUseDOM with a possibility to be a constant (#14194)

https://webpack.js.org/plugins/define-plugin/ Webpack's DefinePlugin has the ability to replace `typeof expr` to a constant in compile-time, which should lead to better dead-code-elimination.
facebook · Apr 25, 2019 · 1eb2b89 · 1eb2b89
1 parent de26d6d
commit 1eb2b89
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/packages/shared/ExecutionEnvironment.js b/packages/shared/ExecutionEnvironment.js
@@ -9,6 +9,6 @@
 
 export const canUseDOM: boolean = !!(
   typeof window !== 'undefined' &&
-  window.document &&
-  window.document.createElement
+  typeof window.document !== 'undefined' &&
+  typeof window.document.createElement !== 'undefined'
 );