Add dynamic navigation tunnel to fly-out menus

app/assets/javascripts/fly_out_nav.js

 import Cookies from 'js-cookie';
 import bp from './breakpoints';
 
+const IS_OVER_CLASS = 'is-over';
+const IS_ABOVE_CLASS = 'is-above';
+const IS_SHOWING_FLY_OUT_CLASS = 'is-showing-fly-out';
+let currentOpenMenu = null;
+let menuCornerLocs;
+let timeoutId;
+
+export const mousePos = [];
+
+export const setOpenMenu = (menu) => { currentOpenMenu = menu; };
+
+export const slope = (a, b) => (b.y - a.y) / (b.x - a.x);
+
 export const canShowActiveSubItems = (el) => {
   const isHiddenByMedia = bp.getBreakpointSize() === 'sm' || bp.getBreakpointSize() === 'md';
 
@@ -10,8 +23,28 @@ export const canShowActiveSubItems = (el) => {
 
   return true;
 };
+
 export const canShowSubItems = () => bp.getBreakpointSize() === 'sm' || bp.getBreakpointSize() === 'md' || bp.getBreakpointSize() === 'lg';
 
+export const getHideSubItemsInterval = () => {
+  if (!currentOpenMenu) return 0;
+
+  const currentMousePos = mousePos[mousePos.length - 1];
+  const prevMousePos = mousePos[0];
+  const currentMousePosY = currentMousePos.y;
+  const [menuTop, menuBottom] = menuCornerLocs;
+
+  if (currentMousePosY < menuTop.y ||
+      currentMousePosY > menuBottom.y) return 0;
+
+  if (slope(prevMousePos, menuBottom) < slope(currentMousePos, menuBottom) &&
+    slope(prevMousePos, menuTop) > slope(currentMousePos, menuTop)) {
+    return 300;
+  }
+
+  return 0;
+};
+
 export const calculateTop = (boundingRect, outerHeight) => {
   const windowHeight = window.innerHeight;
   const bottomOverflow = windowHeight - (boundingRect.top + outerHeight);
@@ -20,45 +53,111 @@ export const calculateTop = (boundingRect, outerHeight) => {
     boundingRect.top;
 };
 
-export const showSubLevelItems = (el) => {
-  const subItems = el.querySelector('.sidebar-sub-level-items');
+export const hideMenu = (el) => {
+  if (!el) return;
 
-  if (!subItems || !canShowSubItems() || !canShowActiveSubItems(el)) return;
+  const parentEl = el.parentNode;
 
-  subItems.style.display = 'block';
-  el.classList.add('is-showing-fly-out');
-  el.classList.add('is-over');
+  el.style.display = ''; // eslint-disable-line no-param-reassign
+  el.style.transform = ''; // eslint-disable-line no-param-reassign
+  el.classList.remove(IS_ABOVE_CLASS);
+  parentEl.classList.remove(IS_OVER_CLASS);
+  parentEl.classList.remove(IS_SHOWING_FLY_OUT_CLASS);
+
+  setOpenMenu(null);
+};
 
+export const moveSubItemsToPosition = (el, subItems) => {
   const boundingRect = el.getBoundingClientRect();
   const top = calculateTop(boundingRect, subItems.offsetHeight);
   const isAbove = top < boundingRect.top;
 
   subItems.classList.add('fly-out-list');
-  subItems.style.transform = `translate3d(0, ${Math.floor(top)}px, 0)`;
+  subItems.style.transform = `translate3d(0, ${Math.floor(top)}px, 0)`; // eslint-disable-line no-param-reassign
+
+  const subItemsRect = subItems.getBoundingClientRect();
+
+  menuCornerLocs = [
+    {
+      x: subItemsRect.left, // left position of the sub items
+      y: subItemsRect.top, // top position of the sub items
+    },
+    {
+      x: subItemsRect.left, // left position of the sub items
+      y: subItemsRect.top + subItemsRect.height, // bottom position of the sub items
+    },
+  ];
 
   if (isAbove) {
-    subItems.classList.add('is-above');
+    subItems.classList.add(IS_ABOVE_CLASS);
   }
 };
 
-export const hideSubLevelItems = (el) => {
+export const showSubLevelItems = (el) => {
+  const subItems = el.querySelector('.sidebar-sub-level-items');
+
+  if (!canShowSubItems() || !canShowActiveSubItems(el)) return;
+
+  el.classList.add(IS_OVER_CLASS);
+
+  if (!subItems) return;
+
+  subItems.style.display = 'block';
+  el.classList.add(IS_SHOWING_FLY_OUT_CLASS);
+
+  setOpenMenu(subItems);
+  moveSubItemsToPosition(el, subItems);
+};
+
+export const mouseEnterTopItems = (el) => {
+  clearTimeout(timeoutId);
+
+  timeoutId = setTimeout(() => {
+    if (currentOpenMenu) hideMenu(currentOpenMenu);
+
+    showSubLevelItems(el);
+  }, getHideSubItemsInterval());
+};
+
+export const mouseLeaveTopItem = (el) => {
   const subItems = el.querySelector('.sidebar-sub-level-items');
 
-  if (!subItems || !canShowSubItems() || !canShowActiveSubItems(el)) return;
+  if (!canShowSubItems() || !canShowActiveSubItems(el) || (subItems && subItems === currentOpenMenu)) return;
 
-  el.classList.remove('is-showing-fly-out');
-  el.classList.remove('is-over');
-  subItems.style.display = '';
-  subItems.style.transform = '';
-  subItems.classList.remove('is-above');
+  el.classList.remove(IS_OVER_CLASS);
+};
+
+export const documentMouseMove = (e) => {
+  mousePos.push({ x: e.clientX, y: e.clientY });
+
+  if (mousePos.length > 6) mousePos.shift();
 };
 
 export default () => {
-  const items = [...document.querySelectorAll('.sidebar-top-level-items > li')]
-    .filter(el => el.querySelector('.sidebar-sub-level-items'));
+  const sidebar = document.querySelector('.sidebar-top-level-items');
+  const items = [...sidebar.querySelectorAll('.sidebar-top-level-items > li')];
+
+  sidebar.addEventListener('mouseleave', () => {
+    clearTimeout(timeoutId);
+
+    timeoutId = setTimeout(() => {
+      if (currentOpenMenu) hideMenu(currentOpenMenu);
+    }, getHideSubItemsInterval());
+  });
 
   items.forEach((el) => {
-    el.addEventListener('mouseenter', e => showSubLevelItems(e.currentTarget));
-    el.addEventListener('mouseleave', e => hideSubLevelItems(e.currentTarget));
+    const subItems = el.querySelector('.sidebar-sub-level-items');
+
+    if (subItems) {
+      subItems.addEventListener('mouseleave', () => {
+        clearTimeout(timeoutId);
+        hideMenu(currentOpenMenu);
+      });
+    }
+
+    el.addEventListener('mouseenter', e => mouseEnterTopItems(e.currentTarget));
+    el.addEventListener('mouseleave', e => mouseLeaveTopItem(e.currentTarget));
   });
+
+  document.addEventListener('mousemove', documentMouseMove);
 };

app/assets/stylesheets/new_sidebar.scss

@@ -250,32 +250,13 @@ $new-sidebar-collapsed-width: 50px;
             position: absolute;
             top: -30px;
             bottom: -30px;
-            left: 0;
+            left: -10px;
             right: -30px;
             z-index: -1;
           }
 
-          &::after {
-            content: "";
-            position: absolute;
-            top: 44px;
-            left: -30px;
-            right: 35px;
-            bottom: 0;
-            height: 100%;
-            max-height: 150px;
-            z-index: -1;
-            transform: skew(33deg);
-          }
-
           &.is-above {
             margin-top: 1px;
-
-            &::after {
-              top: auto;
-              bottom: 44px;
-              transform: skew(-30deg);
-            }
           }
 
           > .active {
@@ -322,8 +303,7 @@ $new-sidebar-collapsed-width: 50px;
       }
     }
 
-    &:not(.active):hover > a,
-    > a:hover,
+    &.active > a:hover,
     &.is-over > a {
       background-color: $white-light;
     }

spec/javascripts/fly_out_nav_spec.js

 import Cookies from 'js-cookie';
 import {
   calculateTop,
-  hideSubLevelItems,
   showSubLevelItems,
   canShowSubItems,
   canShowActiveSubItems,
+  mouseEnterTopItems,
+  mouseLeaveTopItem,
+  setOpenMenu,
+  mousePos,
+  getHideSubItemsInterval,
+  documentMouseMove,
 } from '~/fly_out_nav';
 import bp from '~/breakpoints';
 
-describe('Fly out sidebar navigation', () => {
+fdescribe('Fly out sidebar navigation', () => {
   let el;
   let breakpointSize = 'lg';
 
@@ -18,11 +23,14 @@ describe('Fly out sidebar navigation', () => {
     document.body.appendChild(el);
 
     spyOn(bp, 'getBreakpointSize').and.callFake(() => breakpointSize);
+
+    setOpenMenu(null);
   });
 
   afterEach(() => {
     el.remove();
     breakpointSize = 'lg';
+    mousePos.length = 0;
   });
 
   describe('calculateTop', () => {
@@ -49,61 +57,152 @@ describe('Fly out sidebar navigation', () => {
     });
   });
 
-  describe('hideSubLevelItems', () => {
+  describe('getHideSubItemsInterval', () => {
     beforeEach(() => {
-      el.innerHTML = '<div class="sidebar-sub-level-items"></div>';
+      el.innerHTML = '<div class="sidebar-sub-level-items" style="position: absolute; top: 0; left: 100px; height: 200px;"></div>';
     });
 
-    it('hides subitems', () => {
-      hideSubLevelItems(el);
+    it('returns 0 if currentOpenMenu is nil', () => {
+      expect(
+        getHideSubItemsInterval(),
+      ).toBe(0);
+    });
+
+    it('returns 0 when mouse above sub-items', () => {
+      showSubLevelItems(el);
+      documentMouseMove({
+        clientX: el.getBoundingClientRect().left,
+        clientY: el.getBoundingClientRect().top,
+      });
+      documentMouseMove({
+        clientX: el.getBoundingClientRect().left,
+        clientY: el.getBoundingClientRect().top - 50,
+      });
 
       expect(
-        el.querySelector('.sidebar-sub-level-items').style.display,
-      ).toBe('');
+        getHideSubItemsInterval(),
+      ).toBe(0);
     });
 
-    it('does not hude subitems on mobile', () => {
-      breakpointSize = 'xs';
+    it('returns 0 when mouse is below sub-items', () => {
+      const subItems = el.querySelector('.sidebar-sub-level-items');
 
-      hideSubLevelItems(el);
+      showSubLevelItems(el);
+      documentMouseMove({
+        clientX: el.getBoundingClientRect().left,
+        clientY: el.getBoundingClientRect().top,
+      });
+      documentMouseMove({
+        clientX: el.getBoundingClientRect().left,
+        clientY: (el.getBoundingClientRect().top - subItems.getBoundingClientRect().height) + 50,
+      });
 
       expect(
-        el.querySelector('.sidebar-sub-level-items').style.display,
-      ).not.toBe('none');
+        getHideSubItemsInterval(),
+      ).toBe(0);
     });
 
-    it('removes is-over class', () => {
+    it('returns 300 when mouse is moved towards sub-items', () => {
+      documentMouseMove({
+        clientX: el.getBoundingClientRect().left,
+        clientY: el.getBoundingClientRect().top,
+      });
+      showSubLevelItems(el);
+      documentMouseMove({
+        clientX: el.getBoundingClientRect().left + 20,
+        clientY: el.getBoundingClientRect().top + 10,
+      });
+
+      expect(
+        getHideSubItemsInterval(),
+      ).toBe(300);
+    });
+  });
+
+  describe('mouseLeaveTopItem', () => {
+    beforeEach(() => {
       spyOn(el.classList, 'remove');
+    });
 
-      hideSubLevelItems(el);
+    it('removes is-over class if currentOpenMenu is null', () => {
+      mouseLeaveTopItem(el);
 
       expect(
         el.classList.remove,
       ).toHaveBeenCalledWith('is-over');
     });
 
-    it('removes is-above class from sub-items', () => {
-      const subItems = el.querySelector('.sidebar-sub-level-items');
+    it('removes is-over class if currentOpenMenu is null & there are sub-items', () => {
+      el.innerHTML = '<div class="sidebar-sub-level-items" style="position: absolute;"></div>';
+
+      mouseLeaveTopItem(el);
+
+      expect(
+        el.classList.remove,
+      ).toHaveBeenCalledWith('is-over');
+    });
+
+    it('does not remove is-over class if currentOpenMenu is the passed in sub-items', () => {
+      el.innerHTML = '<div class="sidebar-sub-level-items" style="position: absolute;"></div>';
+
+      setOpenMenu(el.querySelector('.sidebar-sub-level-items'));
+      mouseLeaveTopItem(el);
+
+      expect(
+        el.classList.remove,
+      ).not.toHaveBeenCalled();
+    });
+  });
 
-      spyOn(subItems.classList, 'remove');
+  describe('mouseEnterTopItems', () => {
+    beforeEach(() => {
+      jasmine.clock().install();
 
-      hideSubLevelItems(el);
+      el.innerHTML = '<div class="sidebar-sub-level-items" style="position: absolute; top: 0; left: 100px; height: 200px;"></div>';
+    });
+
+    afterEach(() => {
+      jasmine.clock().uninstall();
+    });
+
+    it('shows sub-items after 0ms if no menu is open', () => {
+      mouseEnterTopItems(el);
 
       expect(
-        subItems.classList.remove,
-      ).toHaveBeenCalledWith('is-above');
+        getHideSubItemsInterval(),
+      ).toBe(0);
+
+      jasmine.clock().tick(0);
+
+      expect(
+        el.querySelector('.sidebar-sub-level-items').style.display,
+      ).toBe('block');
     });
 
-    it('does nothing if el has no sub-items', () => {
-      el.innerHTML = '';
+    it('shows sub-items after 300ms if a menu is currently open', () => {
+      documentMouseMove({
+        clientX: el.getBoundingClientRect().left,
+        clientY: el.getBoundingClientRect().top,
+      });
 
-      spyOn(el.classList, 'remove');
+      setOpenMenu(el.querySelector('.sidebar-sub-level-items'));
+
+      documentMouseMove({
+        clientX: el.getBoundingClientRect().left + 20,
+        clientY: el.getBoundingClientRect().top + 10,
+      });
 
-      hideSubLevelItems(el);
+      mouseEnterTopItems(el);
 
       expect(
-        el.classList.remove,
-      ).not.toHaveBeenCalledWith();
+        getHideSubItemsInterval(),
+      ).toBe(300);
+
+      jasmine.clock().tick(300);
+
+      expect(
+        el.querySelector('.sidebar-sub-level-items').style.display,
+      ).toBe('block');
     });
   });
 
@@ -132,7 +231,7 @@ describe('Fly out sidebar navigation', () => {
       ).not.toBe('block');
     });
 
-    it('does not shows sub-items', () => {
+    it('shows sub-items', () => {
       showSubLevelItems(el);
 
       expect(