protect place order button if user not logged in

ecom-web/src/components/checkout/SubmitOrder.js

 import React, { useState, useEffect } from 'react'
+import {useSelector} from 'react-redux';
 
 export default function SubmitOrder(props) {
 
+    const {currentUser} = useSelector(state => state);
+    
     let handleSubmitClick = (e) => {
         console.log("Submit Button Clicked")
 
@@ -18,7 +21,10 @@ export default function SubmitOrder(props) {
 
             <div id="SubmitButtonContainer">
                 <p className="errorMessage">{(props.errorWhileValidating === 1 && props.allFieldsValidated[0] === 0)? 'One or more fields is missing a value' : ''}</p>
-                <button id="SubmitButtonInput" onClick={() => {handleSubmitClick()}} >Submit Order</button>
+                <button 
+                id="SubmitButtonInput" 
+                onClick={() => {handleSubmitClick()}}
+                disabled={currentUser ? false : true} >Submit Order</button>
             </div>
 
         </div>