get rid of some IE9+ features

Author: Edward Drapkin

src/makeConfiguration.js

@@ -15,7 +15,7 @@ export default (userConfiguration = {}) => {
         errorWhenNotFound: true
     };
 
-    Object.keys(userConfiguration).forEach(name => {
+    for(const name in userConfiguration) {
         const value = userConfiguration[name];
 
         if (!(name in configuration)) {
@@ -27,7 +27,7 @@ export default (userConfiguration = {}) => {
         }
 
         configuration[name] = value;
-    });
+    }
 
     return configuration;
 };

src/parseStyleName.js

@@ -1,12 +1,13 @@
 const styleNameIndex = {};
+import {trim, filterForTruthy} from './utils';
 
 export default (styleNamePropertyValue: string, allowMultiple: boolean): Array<string> => {
     let styleNames;
 
     if (styleNameIndex[styleNamePropertyValue]) {
         styleNames = styleNameIndex[styleNamePropertyValue];
     } else {
-        styleNames = styleNamePropertyValue.trim().split(' ').filter(e => !!e);
+        styleNames = filterForTruthy(trim(styleNamePropertyValue).split(' '));
 
         styleNameIndex[styleNamePropertyValue] = styleNames;
     }

src/utils.js

@@ -11,4 +11,19 @@ export function isFunction(func) {
 
 export function isArray(arr) {
     return Array.isArray ? Array.isArray(arr) : Object.prototype.toString.call(arr) === '[object Array]';
-}
+}
+
+export function trim(str) {
+    return String.prototype.trim ? str.trim() : str.replace(/^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g, '');
+}
+
+export function filterForTruthy(arr) {
+    const results = [];
+    for(const key in arr) {
+        if(arr[key]) {
+            results.push(arr[key]);
+        }
+    }
+
+    return results;
+}