get rid of jQuery.is( usages

addon/src/-private/element.js

@@ -0,0 +1,18 @@
+/**
+ * Borrowed from jquery https://github.com/jquery/jquery/blob/a684e6ba836f7c553968d7d026ed7941e1a612d8/src/css/hiddenVisibleSelectors.js
+ *
+ * Elements are considered visible if they consume space in the document. Visible elements have a width or height that is greater than zero.
+ *
+ * Elements with visibility: hidden or opacity: 0 are considered visible, since they still consume space in the layout.
+ *
+ * @private
+ * @param {Element} element
+ * @returns boolean
+ */
+export function isVisible(element) {
+  return !!(
+    element.offsetWidth ||
+    element.offsetHeight ||
+    element.getClientRects().length
+  );
+}

addon/src/properties/is-hidden.js

@@ -1,6 +1,7 @@
-import { guardMultiple, $ } from '../-private/helpers';
+import { guardMultiple } from '../-private/helpers';
 import { findMany } from '../-private/finders';
 import { getter } from '../macros/index';
+import { isVisible } from '../-private/element';
 
 /**
  * Validates if an element or set of elements is hidden or does not exist in the DOM.
@@ -82,6 +83,6 @@ export function isHidden(selector, userOptions = {}) {
 
     guardMultiple(elements, selector);
 
-    return elements.length === 0 || $(elements[0]).is(':hidden');
+    return elements.length === 0 || !isVisible(elements[0]);
   });
 }

addon/src/properties/is-visible.js

@@ -1,6 +1,7 @@
-import { guardMultiple, $ } from '../-private/helpers';
+import { guardMultiple } from '../-private/helpers';
 import { findMany } from '../-private/finders';
 import { getter } from '../macros/index';
+import { isVisible as isElementVisible } from '../-private/element';
 
 /**
  * Validates if an element or set of elements are visible.
@@ -87,6 +88,6 @@ export function isVisible(selector, userOptions = {}) {
     let elements = findMany(this, selector, options);
     guardMultiple(elements, selector, options.multiple);
 
-    return elements.length === 1 && $(elements[0]).is(':visible');
+    return elements.length === 1 && isElementVisible(elements[0]);
   });
 }