Migrate assets to use Webpacker

app/javascript/src/javascripts/post_popular.js

@@ -0,0 +1,38 @@
+import Utility from './utility'
+
+let PostPopular = {};
+
+PostPopular.nav_prev = function(e) {
+  if ($("#popular-nav-links").length) {
+    var href = $("#popular-nav-links a[rel=prev]").attr("href");
+    if (href) {
+      location.href = href;
+    }
+  }
+
+  e.preventDefault();
+}
+
+PostPopular.nav_next = function(e) {
+  if ($("#popular-nav-links").length) {
+    var href = $("#popular-nav-links a[rel=next]").attr("href");
+    if (href) {
+      location.href = href;
+    }
+  }
+
+  e.preventDefault();
+}
+
+PostPopular.initialize_all = function() {
+  if ($("#c-explore-posts").length) {
+    Utility.keydown("a left", "prev_page", PostPopular.nav_prev);
+    Utility.keydown("d right", "next_page", PostPopular.nav_next);
+  }
+}
+
+$(document).ready(function() {
+  PostPopular.initialize_all();
+});
+
+export default PostPopular