Extract hasDuplicates function

src/api/endpoints/posts/create.js

@@ -4,6 +4,7 @@
  * Module dependencies
  */
 import validate from '../../validator';
+import hasDuplicates from '../../../common/has-duplicates';
 import parse from '../../../common/text';
 import { Post, isValidText } from '../../models/post';
 import User from '../../models/user';
@@ -15,10 +16,6 @@ import notify from '../../common/notify';
 import event from '../../event';
 import config from '../../../conf';
 
-function hasDuplicates(array) {
-	return (new Set(array)).size !== array.length;
-}
-
 /**
  * Create a post
  *

src/common/has-duplicates.ts

@@ -0,0 +1 @@
+export default (array: any[]) => (new Set(array)).size !== array.length;