Merge pull request #9 from TedDriggs/typescript-types

Tighten the className property on custom renderer props in TS declaration

Author: xobotyi

index.d.ts

@@ -1,7 +1,10 @@
 import { Component, CSSProperties, SFC } from "react";
 
+/**
+ * Props passed to custom renderers by `Scrollbar`.
+ */
 export interface ScrollbarRendererProps {
-    className?: string | string[];
+    className: string;
     style?: CSSProperties;
 }