When supported, mark scroll listener as passive (#45)

* feat: Implement passive listener feature detection

* feat(scroll): When supported, mark scroll listener as passive

Closes #38

src/Scroll/Scroll.tsx

@@ -9,6 +9,7 @@ import * as React from 'react';
 import { SharedRenderProps } from '../types';
 import { isEmptyChildren } from '../utils';
 import { throttle } from '../utils/throttle';
+import { supportsPassiveListener } from '../utils/featureDetection';
 
 export interface ScrollProps {
   x: number;
@@ -35,7 +36,11 @@ export class Scroll extends React.Component<
 
   componentDidMount() {
     this.handleWindowScroll();
-    window.addEventListener('scroll', this.handleWindowScroll);
+    (window as EventTarget).addEventListener(
+      'scroll',
+      this.handleWindowScroll,
+      supportsPassiveListener ? { passive: true } : false
+    );
   }
 
   componentWillUnmount() {

src/utils/featureDetection.ts

@@ -0,0 +1,11 @@
+export let supportsPassiveListener = false;
+
+try {
+  const opts = Object.defineProperty({}, 'passive', {
+    get: function() {
+      supportsPassiveListener = true;
+    },
+  });
+  (window as EventTarget).addEventListener('testPassive', null, opts);
+  (window as EventTarget).removeEventListener('testPassive', null, opts);
+} catch (e) {}