Merge pull request #674 from rofrischmann/perf/useFela-props

perf(useFela): optimize passing of theme & props

Author: robinweser

packages/react-fela/src/useFela.js

@@ -15,11 +15,15 @@ export default function useFela(props: Object = {}): HookInterface {
   const renderer = useContext(RendererContext)
   const theme = useContext(ThemeContext) || {}
 
-  const propsWithTheme = {
-    ...props,
-    theme,
+  if (!renderer) {
+    throw new Error(
+      'The "useFela" hook can only be used  inside a "RendererProvider"'
+    )
   }
 
+  const propsWithTheme = { theme }
+  if (props) Object.assign(propsWithTheme, props)
+
   function css(...rules: Array<Object | Function>) {
     return renderer.renderRule(combineRules(...rules), propsWithTheme)
   }