maint(Docs): Document core.dom.is_visible.

Author: thet

src/core/dom.js

@@ -80,6 +80,18 @@ const show = (el) => {
     delete el[DATA_STYLE_DISPLAY];
 };
 
+/**
+ * Test, if a element is visible or not.
+ *
+ * @param {Node} el - The DOM node to test.
+ * @returns {Boolean} - True if the element is visible.
+ */
+const is_visible = (el) => {
+    // Check, if element is visible in DOM.
+    // https://stackoverflow.com/a/19808107/1337474
+    return el.offsetWidth > 0 && el.offsetHeight > 0;
+};
+
 /**
  * Return all direct parents of ``el`` matching ``selector``.
  * This matches against all parents but not the element itself.
@@ -169,12 +181,6 @@ const acquire_attribute = (
     }
 };
 
-const is_visible = (el) => {
-    // Check, if element is visible in DOM.
-    // https://stackoverflow.com/a/19808107/1337474
-    return el.offsetWidth > 0 && el.offsetHeight > 0;
-};
-
 /**
  * Return a DocumentFragment from a given string.
  *