Move main files into client/main

client/main/WindowSize.js

@@ -0,0 +1,35 @@
+import React from "react";
+import PropTypes from "prop-types";
+
+import addEvent from "../utils/addEvent";
+import removeEvent from "../utils/removeEvent";
+
+const resizeEvent = "resize";
+
+class WindowSize extends React.Component {
+  static propTypes = {
+    onChange: PropTypes.func
+  };
+
+  handleWindowResize = () => {
+    if (this.props.onChange)
+      this.props.onChange({
+        width: window.innerWidth,
+        height: window.innerHeight
+      });
+  };
+
+  componentDidMount() {
+    addEvent(window, resizeEvent, this.handleWindowResize);
+  }
+
+  componentWillUnmount() {
+    removeEvent(window, resizeEvent, this.handleWindowResize);
+  }
+
+  render() {
+    return null;
+  }
+}
+
+export default WindowSize;