🔥 get ride of jQuery usage in ember-anchor component

Author: dbendaou

app/components/ember-anchor.js

@@ -1,18 +1,28 @@
-import $ from 'jquery';
 import { get } from '@ember/object';
 import AnchorComponent from 'ember-anchor/components/ember-anchor';
 import config from 'ember-api-docs/config/environment';
 
 export default AnchorComponent.extend({
+  getOffset(element, container) {
+    let offsetTop = element.offsetTop;
+    let parent = element.offsetParent;
+    while (parent != null && parent != container) {
+      offsetTop  += parent.offsetTop;
+      parent = parent.offsetParent;
+    }
+    return offsetTop;
+  },
 
   // This overrides Ember Anchor to support scrolling within a fixed position element
   _scrollToElemPosition() {
     let qp = this.anchorQueryParam;
     let qpVal = this.get(get(this, 'attrs.a') ? 'a' : `controller.${qp}`);
-    let elem = $(`[data-${qp}="${qpVal}"]`);
-    let offset = elem.offset() ? elem.offset().top : 0;
+    let elem = document.querySelector(`[data-${qp}="${qpVal}"]`);
+    let offset = elem.offsetHeight ? elem.offsetHeight : 0;
+
     if (offset) {
-      $(config.APP.scrollContainerSelector).scrollTop(offset);
+      const offsetTop = this.getOffset(elem, config.APP.scrollContainerSelector)
+      document.querySelector(config.APP.scrollContainerSelector).scrollTo(0, offsetTop);
     }
   }
 });