From 310409e18961e1175bd79bbc8b9efceaab7e7f39 Mon Sep 17 00:00:00 2001 From: Brian DeLancey Date: Fri, 6 Sep 2019 05:41:13 -0500 Subject: [PATCH] [core] Guard against bad Symbol polyfills (#17336) --- packages/material-ui-styles/src/ThemeProvider/nested.js | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/packages/material-ui-styles/src/ThemeProvider/nested.js b/packages/material-ui-styles/src/ThemeProvider/nested.js index 5e75d0d8dabf9c..24ca888da9d5ea 100644 --- a/packages/material-ui-styles/src/ThemeProvider/nested.js +++ b/packages/material-ui-styles/src/ThemeProvider/nested.js @@ -1,3 +1,3 @@ -const hasSymbol = typeof Symbol === 'function'; +const hasSymbol = typeof Symbol === 'function' && Symbol.for; export default (hasSymbol ? Symbol.for('mui.nested') : '__THEME_NESTED__');