add ParallaxProvider component that uses context to pass children a reference to controller instance

Author: jscottsmith

src/components/ParallaxProvider.js

@@ -0,0 +1,42 @@
+import React, { Component } from 'react';
+import PropTypes from 'prop-types';
+import { ParallaxController } from 'react-scroll-parallax';
+
+export default class ParallaxProvider extends Component {
+    static propTypes = {
+        children: PropTypes.node.isRequired,
+    };
+
+    static childContextTypes = {
+        parallaxController: PropTypes.object,
+    };
+
+    getChildContext() {
+        // Passes down the reference to the controller
+        const { parallaxController } = this;
+        return { parallaxController };
+    }
+
+    componentWillMount() {
+        // Don't initialize on the server
+        const isServer = typeof window === 'undefined';
+
+        if (!isServer) {
+            // Must not be the server so kick it off...
+            this.parallaxController = ParallaxController.init();
+        }
+    }
+
+    componentWillUnmount() {
+        if (this.parallaxController) {
+            // Remove scroll and resize listener if the provider is unmounted
+            this.parallaxController.destroy();
+        }
+    }
+
+    render() {
+        const { children } = this.props;
+
+        return children;
+    }
+}

src/index.js

@@ -1,2 +1,3 @@
 export Parallax from './components/Parallax';
+export ParallaxProvider from './components/ParallaxProvider';
 export ParallaxController from './libs/ParallaxController';