refactor: flow typing (#1012)

* fix: padding

* fix: Minor button alignment issues

* feat: Add icon to invite people button

* WIP

shared/utils/naturalSort.js

@@ -1,11 +1,36 @@
 // @flow
-import { sortBy } from 'lodash';
+import { deburr } from 'lodash';
 import naturalSort from 'natural-sort';
 
-export default (sortableArray: *, key: string): * => {
-  if (!sortableArray) return [];
-
-  let keys = sortableArray.map(object => object[key]);
-  keys.sort(naturalSort());
-  return sortBy(sortableArray, object => keys.indexOf(object[key]));
+type NaturalSortOptions = {
+  caseSensitive?: boolean,
+  direction?: 'asc' | 'desc',
 };
+
+const sorter = naturalSort();
+
+function getSortByField<T: Object>(
+  item: T,
+  keyOrCallback: string | (T => string)
+) {
+  if (typeof keyOrCallback === 'string') {
+    return deburr(item[keyOrCallback]);
+  }
+
+  return keyOrCallback(item);
+}
+
+function naturalSortBy<T>(
+  items: T[],
+  key: string | (T => string),
+  sortOptions?: NaturalSortOptions
+): T[] {
+  if (!items) return [];
+
+  const sort = sortOptions ? naturalSort(sortOptions) : sorter;
+  return items.sort((a: any, b: any): -1 | 0 | 1 =>
+    sort(getSortByField(a, key), getSortByField(b, key))
+  );
+}
+
+export default naturalSortBy;