select first option from google autocomplete for location input

app/views/location.ejs

@@ -99,6 +99,7 @@
     autocomplete = new google.maps.places.Autocomplete(inputElement, initialAutocompleteParams);
     autocomplete.bindTo('bounds', map);
     autocomplete.addListener('place_changed', onPlaceChanged);
+    pacSelectFirst(inputElement);
   }
 
   function onPlaceChanged() {
@@ -110,6 +111,38 @@
     }
   }
 
+  function pacSelectFirst(input) {
+    // store the original event binding function
+    const _addEventListener = input.addEventListener
+            ? input.addEventListener
+            : input.attachEvent
+
+    function addEventListenerWrapper (type, listener) {
+      // Simulate a 'down arrow' keypress on hitting 'return' when no pac suggestion is selected,
+      // and then trigger the original listener.
+      if (type == 'keydown') {
+        const originalListener = listener
+        listener = function (event) {
+          const suggestionSelected = $('.pac-item-selected').length > 0
+          if (event.key == 'Enter' && !suggestionSelected) {
+            const simulatedDownArrow = $.Event('keydown', {
+              keyCode: 40,
+              which: 40
+            })
+            originalListener.apply(input, [simulatedDownArrow])
+          }
+
+          originalListener.apply(input, [event])
+        }
+      }
+
+      _addEventListener.apply(input, [type, listener])
+    }
+
+    input.addEventListener = addEventListenerWrapper
+    input.attachEvent = addEventListenerWrapper
+  }
+
   $(document).ready(() => {
     $("#submit").click(() => {
       const mapBounds = map.getBounds();