Update to new Django admin styles for v3.x

media/admin/js/collapse.js

@@ -1,24 +1,43 @@
-(function($) {
-	$(document).ready(function() {
-		// Add anchor tag for Show/Hide link
-		$("fieldset.collapse").each(function(i, elem) {
-			// Don't hide if fields in this fieldset have errors
-			if ($(elem).find("div.errors").length == 0) {
-				$(elem).addClass("collapsed").find("h2").first().append(' (<a id="fieldsetcollapser' +
-					i +'" class="collapse-toggle" href="#">' + gettext("Show") +
-					'</a>)');
-			}
-		});
-		// Add toggle to anchor tag
-		$("fieldset.collapse a.collapse-toggle").click(function(ev) {
-			if ($(this).closest("fieldset").hasClass("collapsed")) {
-				// Show
-				$(this).text(gettext("Hide")).closest("fieldset").removeClass("collapsed").trigger("show.fieldset", [$(this).attr("id")]);
-			} else {
-				// Hide
-				$(this).text(gettext("Show")).closest("fieldset").addClass("collapsed").trigger("hide.fieldset", [$(this).attr("id")]);
-			}
-			return false;
-		});
-	});
-})(django.jQuery);
+/*global gettext*/
+'use strict';
+{
+    window.addEventListener('load', function() {
+        // Add anchor tag for Show/Hide link
+        const fieldsets = document.querySelectorAll('fieldset.collapse');
+        for (const [i, elem] of fieldsets.entries()) {
+            // Don't hide if fields in this fieldset have errors
+            if (elem.querySelectorAll('div.errors, ul.errorlist').length === 0) {
+                elem.classList.add('collapsed');
+                const h2 = elem.querySelector('h2');
+                const link = document.createElement('a');
+                link.id = 'fieldsetcollapser' + i;
+                link.className = 'collapse-toggle';
+                link.href = '#';
+                link.textContent = gettext('Show');
+                h2.appendChild(document.createTextNode(' ('));
+                h2.appendChild(link);
+                h2.appendChild(document.createTextNode(')'));
+            }
+        }
+        // Add toggle to hide/show anchor tag
+        const toggleFunc = function(ev) {
+            if (ev.target.matches('.collapse-toggle')) {
+                ev.preventDefault();
+                ev.stopPropagation();
+                const fieldset = ev.target.closest('fieldset');
+                if (fieldset.classList.contains('collapsed')) {
+                    // Show
+                    ev.target.textContent = gettext('Hide');
+                    fieldset.classList.remove('collapsed');
+                } else {
+                    // Hide
+                    ev.target.textContent = gettext('Show');
+                    fieldset.classList.add('collapsed');
+                }
+            }
+        };
+        document.querySelectorAll('fieldset.module').forEach(function(el) {
+            el.addEventListener('click', toggleFunc);
+        });
+    });
+}