when adding a chipTheme, try and merge with the default theme in order to try and override already configured default

- added a deep merge function to handle this scenario

Author: SerjSmor

src/Chip.js

@@ -5,7 +5,9 @@ import themeable from 'react-themeable';
 import { chipTheme } from './theme';
 
 const Chip = ({ selected, theme, onRemove, children }) => {
-  const themr = themeable(theme);
+  // if someone provided a theme, try and merge between the original and provided
+  const mergedTheme = deepMerge(chipTheme, theme);
+  const themr = themeable(mergedTheme);
   return (
     <div {...themr(1, 'chip', selected  ? 'chipSelected' : '')}>
       {children}
@@ -27,4 +29,25 @@ Chip.defaultProps = {
   selected: false,
 }
 
+// from https://stackoverflow.com/a/49798508/1824521
+const deepMerge = (...sources) => {
+  let acc = {}
+  for (const source of sources) {
+    if (source instanceof Array) {
+      if (!(acc instanceof Array)) {
+        acc = []
+      }
+      acc = [...acc, ...source]
+    } else if (source instanceof Object) {
+      for (let [key, value] of Object.entries(source)) {
+        if (value instanceof Object && key in acc) {
+          value = deepMerge(acc[key], value)
+        }
+        acc = { ...acc, [key]: value }
+      }
+    }
+  }
+  return acc
+}
+
 export default Radium(Chip);