js: Only load Google Maps scripts when required (Close #317)

layouts/partials/footer.html

@@ -7,8 +7,6 @@
 
     {{ if .Site.Params.google_maps_api_key }}
     <script async defer src="//maps.googleapis.com/maps/api/js?key={{ .Site.Params.google_maps_api_key }}"></script>
-    {{ else }}
-    <script async defer src="//maps.googleapis.com/maps/api/js"></script>
     {{ end }}
 
     {{ if not .Site.Params.disable_sri }}
@@ -16,14 +14,18 @@
     {{ printf "<script src=\"https://cdnjs.cloudflare.com/ajax/libs/jquery.imagesloaded/%s/imagesloaded.pkgd.min.js\" integrity=\"%s\" crossorigin=\"anonymous\"></script>" $js.imagesLoaded.version $js.imagesLoaded.sri | safeHTML }}
     {{ printf "<script src=\"https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/%s/js/bootstrap.min.js\" integrity=\"%s\" crossorigin=\"anonymous\"></script>" $js.bootstrap.version $js.bootstrap.sri | safeHTML }}
     {{ printf "<script src=\"https://cdnjs.cloudflare.com/ajax/libs/jquery.isotope/%s/isotope.pkgd.min.js\" integrity=\"%s\" crossorigin=\"anonymous\"></script>" $js.isotope.version $js.isotope.sri | safeHTML }}
+    {{ if .Site.Params.google_maps_api_key }}
     {{ printf "<script src=\"https://cdnjs.cloudflare.com/ajax/libs/gmaps.js/%s/gmaps.min.js\" integrity=\"%s\" crossorigin=\"anonymous\"></script>" $js.gmaps.version $js.gmaps.sri | safeHTML }}
+    {{ end }}
     {{ else }}
     <script src="//cdnjs.cloudflare.com/ajax/libs/jquery/{{- $js.jQuery.version -}}/jquery.min.js"></script>
     <script src="//cdnjs.cloudflare.com/ajax/libs/jquery.imagesloaded/{{- $js.imagesLoaded.version -}}/imagesloaded.pkgd.min.js"></script>
     <script src="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/{{- $js.bootstrap.version -}}/js/bootstrap.min.js"></script>
     <script src="//cdnjs.cloudflare.com/ajax/libs/jquery.isotope/{{- $js.isotope.version -}}/isotope.pkgd.min.js"></script>
+    {{ if .Site.Params.google_maps_api_key }}
     <script src="//cdnjs.cloudflare.com/ajax/libs/gmaps.js/{{- $js.gmaps.version -}}/gmaps.min.js"></script>
     {{ end }}
+    {{ end }}
     <script src="{{ "/js/hugo-academic.js" | relURL }}"></script>
     {{ range .Site.Params.custom_js }}
     <script src="{{ "/js/" | relURL }}{{ . }}"></script>