improve plugin system & add and improve various tests

2026-05-17 06:19:39 +03:00 · 2022-08-24 16:47:19 +02:00
parent 0d10faccd0
commit b7ebfd3dbd
9 changed files with 727 additions and 140 deletions
@@ -1,4 +1,13 @@
-import { assignDeep, each, isObject, keys, isArray, hasOwnProperty, isFunction } from 'support';
+import {
+  assignDeep,
+  each,
+  isObject,
+  keys,
+  isArray,
+  hasOwnProperty,
+  isFunction,
+  isEmptyObject,
+} from 'support';
 import { DeepPartial, DeepReadonly } from 'typings';

 const opsStringify = (value: any) =>
@@ -80,6 +89,10 @@ export const getOptionsDiff = <T>(currOptions: T, newOptions: DeepPartial<T>): D

    if (isObject(currOptionValue) && isObject(newOptionValue)) {
      assignDeep((diff[optionKey] = {}), getOptionsDiff(currOptionValue, newOptionValue));
+      // delete empty nested objects
+      if (isEmptyObject(diff[optionKey])) {
+        delete diff[optionKey];
+      }
    } else if (hasOwnProperty(newOptions, optionKey) && newOptionValue !== currOptionValue) {
      let isDiff = true;

@@ -13,7 +13,7 @@ import { getEnvironment } from 'environment';
 import { cancelInitialization } from 'initialization';
 import { addInstance, getInstance, removeInstance } from 'instances';
 import { createStructureSetup, createScrollbarsSetup } from 'setups';
-import { getPlugins, addPlugin, optionsValidationPluginName } from 'plugins';
+import { getPlugins, addPlugin, optionsValidationPluginName, PluginInstance } from 'plugins';
 import type { XY, TRBL } from 'support';
 import type { Options, ReadonlyOptions } from 'options';
 import type { Plugin, OptionsValidationPluginInstance } from 'plugins';
@@ -109,6 +109,16 @@ export interface OverlayScrollbars {
  destroy(): void;
 }

+const invokePluginInstance = (
+  pluginInstance: PluginInstance,
+  staticObj?: OverlayScrollbarsStatic | false | null | undefined | 0,
+  instanceObj?: OverlayScrollbars | false | null | undefined | 0
+) => {
+  if (isFunction(pluginInstance)) {
+    pluginInstance(staticObj || undefined, instanceObj || undefined);
+  }
+};
+
 // eslint-disable-next-line @typescript-eslint/no-redeclare
 export const OverlayScrollbars: OverlayScrollbarsStatic = (
  target: InitializationTarget,
@@ -122,13 +132,12 @@ export const OverlayScrollbars: OverlayScrollbarsStatic = (
  const potentialInstance = getInstance(instanceTarget);
  if (options && !potentialInstance) {
    let destroyed = false;
-    const optionsValidationPlugin = plugins[
-      optionsValidationPluginName
-    ] as OptionsValidationPluginInstance;
-    const validateOptions = (newOptions?: DeepPartial<Options>) => {
-      const opts = newOptions || {};
+    const validateOptions = (newOptions: DeepPartial<Options>) => {
+      const optionsValidationPlugin = getPlugins()[
+        optionsValidationPluginName
+      ] as OptionsValidationPluginInstance;
      const validate = optionsValidationPlugin && optionsValidationPlugin._;
-      return validate ? validate(opts, true) : opts;
+      return validate ? validate(newOptions, true) : newOptions;
    };
    const currentOptions: ReadonlyOptions = assignDeep(
      {},
@@ -166,7 +175,6 @@ export const OverlayScrollbars: OverlayScrollbarsStatic = (
      options(newOptions?: DeepPartial<Options>) {
        if (newOptions) {
          const changedOptions = getOptionsDiff(currentOptions, validateOptions(newOptions));
-
          if (!isEmptyObject(changedOptions)) {
            assignDeep(currentOptions, changedOptions);
            update(changedOptions);
@@ -260,12 +268,11 @@ export const OverlayScrollbars: OverlayScrollbarsStatic = (
      updateScrollbars(changedOptions, force, updateHints);
    });

-    each(keys(plugins), (pluginName) => {
-      const pluginInstance = plugins[pluginName];
-      if (isFunction(pluginInstance)) {
-        pluginInstance(OverlayScrollbars, instance);
-      }
-    });
+    // valid inside plugins
+    addInstance(instanceTarget, instance);
+
+    // init plugins
+    each(keys(plugins), (pluginName) => invokePluginInstance(plugins[pluginName], 0, instance));

    if (
      cancelInitialization(
@@ -281,7 +288,6 @@ export const OverlayScrollbars: OverlayScrollbarsStatic = (
    structureState._appendElements();
    scrollbarsState._appendElements();

-    addInstance(instanceTarget, instance);
    triggerEvent('initialized', [instance]);

    structureState._addOnUpdatedListener((updateHints, changedOptions, force) => {
@@ -322,7 +328,11 @@ export const OverlayScrollbars: OverlayScrollbarsStatic = (
  return potentialInstance!;
 };

-OverlayScrollbars.plugin = addPlugin;
+OverlayScrollbars.plugin = (plugins: Plugin | Plugin[]) => {
+  each(addPlugin(plugins), (pluginInstance) =>
+    invokePluginInstance(pluginInstance, OverlayScrollbars)
+  );
+};
 OverlayScrollbars.valid = (osInstance: any): osInstance is OverlayScrollbars => {
  const hasElmsFn = osInstance && (osInstance as OverlayScrollbars).elements;
  const elements = isFunction(hasElmsFn) && hasElmsFn();
@@ -1,9 +1,9 @@
-import { each, isArray, keys } from 'support';
+import { each, isArray, keys, push } from 'support';
 import { OverlayScrollbars, OverlayScrollbarsStatic } from 'overlayscrollbars';

 export type PluginInstance =
  | Record<string, unknown>
-  | ((staticObj: OverlayScrollbarsStatic, instanceObj: OverlayScrollbars) => void);
+  | ((staticObj?: OverlayScrollbarsStatic, instanceObj?: OverlayScrollbars) => void);
 export type Plugin<T extends PluginInstance = PluginInstance> = {
  [pluginName: string]: T;
 };
@@ -12,9 +12,14 @@ const pluginRegistry: Record<string, PluginInstance> = {};

 export const getPlugins = () => pluginRegistry;

-export const addPlugin = (addedPlugin: Plugin | Plugin[]): void => {
+export const addPlugin = (addedPlugin: Plugin | Plugin[]): Plugin[] => {
+  const result: Plugin[] = [];
  each((isArray(addedPlugin) ? addedPlugin : [addedPlugin]) as Plugin[], (plugin) => {
-    const pluginName = keys(plugin)[0];
-    pluginRegistry[pluginName] = plugin[pluginName];
+    // multiple "sub-plugins" per plugin object possible to support "static", "instanceObj" and "staticObj" sub-plugins per plugin
+    const pluginNameKeys = keys(plugin);
+    each(pluginNameKeys, (key) => {
+      push(result, (pluginRegistry[key] = plugin[key]));
+    });
  });
+  return result;
 };
@@ -45,7 +45,7 @@ import type {
 } from 'initialization';

 export type StructureSetupElements = [
-  targetObj: StructureSetupElementsObj,
+  elements: StructureSetupElementsObj,
  appendElements: () => void,
  destroy: () => void
 ];
@@ -41,6 +41,7 @@ describe('options', () => {
        b: 0,
      };

+      expect(getOptionsDiff(options, options)).toEqual({});
      expect(getOptionsDiff(options, changed)).toEqual(changed);

      expect(
@@ -74,6 +75,7 @@ describe('options', () => {
        },
      };

+      expect(getOptionsDiff(options, options)).toEqual({});
      expect(getOptionsDiff(options, changed)).toEqual(changed);

      expect(
@@ -1,6 +1,7 @@
 import { DeepPartial } from 'typings';
 import { defaultOptions, Options } from 'options';
 import { assignDeep } from 'support';
+import { optionsValidationPlugin } from 'plugins';
 import { OverlayScrollbars as originalOverlayScrollbars } from '../../src/overlayscrollbars';

 const bodyElm = document.body;
@@ -155,26 +156,144 @@ describe('overlayscrollbars', () => {
      });
    });

-    test('options', () => {
-      const customOptions: DeepPartial<Options> = {
-        paddingAbsolute: !defaultOptions.paddingAbsolute,
-        overflow: { x: 'hidden' },
-      };
-      const osInstance = OverlayScrollbars(div, {});
-      expect(osInstance.options()).not.toBe(defaultOptions);
-      expect(osInstance.options()).toEqual(defaultOptions);
-      OverlayScrollbars(div)!.destroy();
+    describe('elements', () => {
+      test('get elements', () => {
+        const osInstance = OverlayScrollbars(div, {});
+        const elements = osInstance.elements();
+        const elementsObj = {
+          target: div,
+          host: div,
+          padding: expect.any(HTMLElement),
+          viewport: expect.any(HTMLElement),
+          content: expect.any(HTMLElement),
+          scrollOffsetElement: expect.any(HTMLElement),
+          scrollEventElement: expect.any(HTMLElement),
+          scrollbarHorizontal: {
+            scrollbar: expect.any(HTMLElement),
+            track: expect.any(HTMLElement),
+            handle: expect.any(HTMLElement),
+            clone: expect.any(Function),
+          },
+          scrollbarVertical: {
+            scrollbar: expect.any(HTMLElement),
+            track: expect.any(HTMLElement),
+            handle: expect.any(HTMLElement),
+            clone: expect.any(Function),
+          },
+        };

-      expect(OverlayScrollbars(div, customOptions).options()).toEqual(
-        assignDeep({}, defaultOptions, customOptions)
-      );
-      OverlayScrollbars(div)!.destroy();
+        expect(elements).not.toBe(osInstance.elements());
+        // clone function identity is always different
+        expect(
+          assignDeep({}, elements, {
+            scrollbarHorizontal: {
+              clone: null,
+            },
+            scrollbarVertical: {
+              clone: null,
+            },
+          })
+        ).toEqual(
+          assignDeep({}, osInstance.elements(), {
+            scrollbarHorizontal: {
+              clone: null,
+            },
+            scrollbarVertical: {
+              clone: null,
+            },
+          })
+        );
+        expect(elements).toEqual(elementsObj);

-      const osInstance2 = OverlayScrollbars(div, {});
-      expect(osInstance2.options(customOptions)).toEqual(
-        assignDeep({}, defaultOptions, customOptions)
-      );
-      expect(osInstance2.options()).toEqual(assignDeep({}, defaultOptions, customOptions));
+        osInstance.destroy();
+
+        expect(elements).toEqual(elementsObj);
+      });
+
+      test('clone scrollbars', () => {
+        const osInstance = OverlayScrollbars(div, {});
+        const elements = osInstance.elements();
+
+        const hClone = elements.scrollbarHorizontal.clone();
+        const vClone = elements.scrollbarVertical.clone();
+
+        expect(hClone).toEqual({
+          scrollbar: expect.any(HTMLElement),
+          track: expect.any(HTMLElement),
+          handle: expect.any(HTMLElement),
+        });
+        expect(vClone).toEqual({
+          scrollbar: expect.any(HTMLElement),
+          track: expect.any(HTMLElement),
+          handle: expect.any(HTMLElement),
+        });
+
+        div.append(hClone.scrollbar);
+        div.append(vClone.scrollbar);
+
+        osInstance.destroy();
+
+        expect(div.innerHTML).toBe('');
+      });
+    });
+
+    describe('options', () => {
+      [false, true].forEach((withValidationPlugin) => {
+        describe(`${withValidationPlugin ? 'with' : 'without'} optionsValidationPlugin`, () => {
+          beforeEach(() => {
+            if (withValidationPlugin) {
+              OverlayScrollbars.plugin(optionsValidationPlugin);
+            }
+          });
+
+          test('equality', () => {
+            const osInstance = OverlayScrollbars(div, {});
+            expect(osInstance.options()).not.toBe(defaultOptions);
+            expect(osInstance.options()).toEqual(defaultOptions);
+            OverlayScrollbars(div)!.destroy();
+          });
+
+          test('initial options', () => {
+            const customOptions: DeepPartial<Options> = {
+              paddingAbsolute: !defaultOptions.paddingAbsolute,
+              overflow: { x: 'hidden' },
+            };
+
+            const osInstance = OverlayScrollbars(div, customOptions);
+            expect(osInstance.options()).toEqual(assignDeep({}, defaultOptions, customOptions));
+          });
+
+          test('changed options', () => {
+            const customOptions: DeepPartial<Options> = {
+              paddingAbsolute: !defaultOptions.paddingAbsolute,
+              overflow: { x: 'hidden' },
+            };
+
+            const osInstance = OverlayScrollbars(div, {});
+            expect(osInstance.options(customOptions)).toEqual(
+              assignDeep({}, defaultOptions, customOptions)
+            );
+            expect(osInstance.options()).toEqual(assignDeep({}, defaultOptions, customOptions));
+            osInstance.destroy();
+          });
+
+          test('unchanged wont trigger update', () => {
+            const updated = jest.fn();
+            const initialOpts: DeepPartial<Options> = {
+              paddingAbsolute: true,
+              overflow: {
+                y: 'hidden',
+              },
+            };
+            const osInstance4 = OverlayScrollbars(div, initialOpts, {
+              updated,
+            });
+            expect(updated).toHaveBeenCalledTimes(1);
+            osInstance4.options(initialOpts);
+            expect(updated).toHaveBeenCalledTimes(1);
+          });
+        });
+      });
    });

    test('on', () => {
@@ -296,59 +415,6 @@ describe('overlayscrollbars', () => {
      );
    });

-    test('elements', () => {
-      const osInstance = OverlayScrollbars(div, {});
-      const elements = osInstance.elements();
-      const elementsObj = {
-        target: div,
-        host: div,
-        padding: expect.any(HTMLElement),
-        viewport: expect.any(HTMLElement),
-        content: expect.any(HTMLElement),
-        scrollOffsetElement: expect.any(HTMLElement),
-        scrollEventElement: expect.any(HTMLElement),
-        scrollbarHorizontal: {
-          scrollbar: expect.any(HTMLElement),
-          track: expect.any(HTMLElement),
-          handle: expect.any(HTMLElement),
-          clone: expect.any(Function),
-        },
-        scrollbarVertical: {
-          scrollbar: expect.any(HTMLElement),
-          track: expect.any(HTMLElement),
-          handle: expect.any(HTMLElement),
-          clone: expect.any(Function),
-        },
-      };
-
-      expect(elements).not.toBe(osInstance.elements());
-      // clone function identity is always different
-      expect(
-        assignDeep({}, elements, {
-          scrollbarHorizontal: {
-            clone: null,
-          },
-          scrollbarVertical: {
-            clone: null,
-          },
-        })
-      ).toEqual(
-        assignDeep({}, osInstance.elements(), {
-          scrollbarHorizontal: {
-            clone: null,
-          },
-          scrollbarVertical: {
-            clone: null,
-          },
-        })
-      );
-      expect(elements).toEqual(elementsObj);
-
-      osInstance.destroy();
-
-      expect(elements).toEqual(elementsObj);
-    });
-
    test('update', () => {
      const osInstance = OverlayScrollbars(div, {});
      expect(osInstance.update()).toBe(false);
@@ -405,4 +471,64 @@ describe('overlayscrollbars', () => {
      expect(OverlayScrollbars.valid(osInstance)).toBe(false);
    });
  });
+
+  test('plugins', () => {
+    const staticPluginFn = jest.fn();
+    const staticObjPluginFn = jest.fn();
+    const instanceObjPluginFn = jest.fn();
+    const staticPlugin = {
+      staticPlugin: {
+        staticFn: staticPluginFn,
+      },
+    };
+    expect(
+      OverlayScrollbars.plugin([
+        {
+          expect: (staticObj, instanceObj) => {
+            if (instanceObj) {
+              expect(staticObj).toBe(undefined);
+              expect(OverlayScrollbars.valid(instanceObj)).toBe(true);
+            }
+            if (staticObj) {
+              expect(staticObj).toBe(OverlayScrollbars);
+              expect(instanceObj).toBe(undefined);
+            }
+          },
+        },
+        {
+          staticPlugin,
+          staticObjPlugin: (staticObj, instanceObj) => {
+            if (staticObj) {
+              expect(instanceObj).toBe(undefined);
+              // @ts-ignore
+              staticObj.staticObjPluginFn = staticObjPluginFn;
+            }
+          },
+          instanceObjPlugin: (_, instanceObj) => {
+            if (instanceObj) {
+              // @ts-ignore
+              instanceObj.instanceObjPluginFn = instanceObjPluginFn;
+            }
+          },
+        },
+      ])
+    ).toBe(undefined);
+
+    expect(staticPluginFn).not.toHaveBeenCalled();
+    // @ts-ignore
+    staticPlugin.staticPlugin.staticFn();
+    expect(staticPluginFn).toHaveBeenCalledTimes(1);
+
+    // staticObj plugin must be available before any initialization
+    expect(staticObjPluginFn).not.toHaveBeenCalled();
+    // @ts-ignore
+    OverlayScrollbars.staticObjPluginFn();
+    expect(staticObjPluginFn).toHaveBeenCalledTimes(1);
+
+    const osInstance = OverlayScrollbars(div, {});
+    expect(instanceObjPluginFn).not.toHaveBeenCalled();
+    // @ts-ignore
+    osInstance.instanceObjPluginFn();
+    expect(instanceObjPluginFn).toHaveBeenCalledTimes(1);
+  });
 });
@@ -9,19 +9,24 @@ describe('plugins', () => {
  test('addPlugin single', () => {
    const myPlugin = {};
    const myPlugin2 = {};
-    addPlugin({
+    const addedPlugins = addPlugin({
      myPlugin,
      myPlugin2,
    });
+    expect(addedPlugins.length).toBe(2);
+    expect(addedPlugins[0]).toBe(myPlugin);
+    expect(addedPlugins[1]).toBe(myPlugin2);
+
    const plugins = getPlugins();
    expect(plugins.myPlugin).toBe(myPlugin);
-    expect(plugins.myPlugin2).toBe(undefined); // one plugin per object
+    // multiple "sub-plugins" per plugin object possible to support "static", "instanceObj" and "staticObj" sub-plugins per plugin
+    expect(plugins.myPlugin2).toBe(myPlugin2);
  });

  test('addPlugin multiple', () => {
    const myPlugin = {};
    const myPlugin2 = {};
-    addPlugin([
+    const addedPlugins = addPlugin([
      {
        myPlugin,
      },
@@ -29,6 +34,11 @@ describe('plugins', () => {
        myPlugin2,
      },
    ]);
+
+    expect(addedPlugins.length).toBe(2);
+    expect(addedPlugins[0]).toBe(myPlugin);
+    expect(addedPlugins[1]).toBe(myPlugin2);
+
    const plugins = getPlugins();
    expect(plugins.myPlugin).toBe(myPlugin);
    expect(plugins.myPlugin2).toBe(myPlugin2);
@@ -0,0 +1,363 @@
+import {
+  createScrollbarsSetupElements,
+  ScrollbarsSetupElement,
+  ScrollbarsSetupElementsObj,
+  ScrollbarStructure,
+} from 'setups/scrollbarsSetup/scrollbarsSetup.elements';
+import {
+  createStructureSetupElements,
+  StructureSetupElementsObj,
+} from 'setups/structureSetup/structureSetup.elements';
+import {
+  classNameScrollbar,
+  classNameScrollbarHorizontal,
+  classNameScrollbarVertical,
+  classNameScrollbarTrack,
+  classNameScrollbarHandle,
+  classNamesScrollbarTransitionless,
+} from 'classnames';
+import type { InitializationTarget } from 'initialization';
+
+jest.useFakeTimers();
+
+jest.mock('support/compatibility/apis', () => {
+  const originalModule = jest.requireActual('support/compatibility/apis');
+  return {
+    ...originalModule,
+    // @ts-ignore
+    setT: jest.fn().mockImplementation((...args) => setTimeout(...args)),
+    clearT: jest.fn().mockImplementation((...args) => clearTimeout(...args)),
+  };
+});
+
+const getTarget = () => document.body.firstElementChild as HTMLElement;
+
+const domSnapshot = (element?: HTMLElement) => {
+  const getResult = () => (element ? element.innerHTML : document.documentElement.outerHTML);
+  return [getResult(), () => getResult()] as [string, () => string];
+};
+
+const createStructureSetupElementsProxy = (target: InitializationTarget) => {
+  const [structureElements, , destroyStructureElements] = createStructureSetupElements(target);
+  const [elements, appendElements, destroy] = createScrollbarsSetupElements(
+    target,
+    structureElements,
+    () => () => {}
+  );
+
+  appendElements();
+
+  return [
+    elements,
+    () => {
+      destroyStructureElements();
+      destroy();
+    },
+    structureElements,
+  ] as [
+    elements: ScrollbarsSetupElementsObj,
+    destroy: () => void,
+    structureElements: StructureSetupElementsObj
+  ];
+};
+
+const assertCorrectDOMStructure = (
+  elements: ScrollbarsSetupElementsObj,
+  target: HTMLElement | ((isHorizontal?: boolean) => HTMLElement),
+  getTargetStructure?: (
+    structures: ScrollbarStructure[],
+    isHorizontal?: boolean
+  ) => ScrollbarStructure
+) => {
+  const getStructure = (isHorizontal?: boolean) =>
+    isHorizontal
+      ? elements._horizontal._scrollbarStructures
+      : elements._vertical._scrollbarStructures;
+  const assertScrollbarStructure = (isHorizontal?: boolean) => {
+    const resolvedTarget = typeof target === 'function' ? target(isHorizontal) : target;
+    const domScrollbar = resolvedTarget.querySelector(
+      `.${isHorizontal ? classNameScrollbarHorizontal : classNameScrollbarVertical}`
+    ) as HTMLElement;
+    const structures = getStructure(isHorizontal);
+
+    expect(structures.length).toBeGreaterThanOrEqual(1);
+
+    const targetStructure = getTargetStructure?.(structures, isHorizontal) || structures[0];
+    const isMainStructure = targetStructure === structures[0];
+    const { _scrollbar, _track, _handle } = targetStructure;
+
+    // classnames
+    expect(domScrollbar).toEqual(expect.any(HTMLElement));
+    expect(domScrollbar.classList.contains(classNameScrollbar)).toBe(true);
+    expect(_track.classList.contains(classNameScrollbarTrack)).toBe(true);
+    expect(_handle.classList.contains(classNameScrollbarHandle)).toBe(true);
+    expect(_track.classList.length).toBe(1);
+    expect(_handle.classList.length).toBe(1);
+    if (isMainStructure) {
+      expect(domScrollbar.classList.contains(classNamesScrollbarTransitionless)).toBe(true);
+    }
+
+    // structure
+    expect(_scrollbar).toBe(domScrollbar);
+    expect(_track.closest(`.${classNameScrollbar}`)).toBe(_scrollbar);
+    expect(_handle.closest(`.${classNameScrollbarTrack}`)).toBe(_track);
+  };
+
+  assertScrollbarStructure(true);
+  assertScrollbarStructure();
+};
+
+describe('scrollbarsSetup.elements', () => {
+  beforeEach(() => {
+    document.body.innerHTML = '<div></div>';
+  });
+
+  [false, true].forEach((targetIsObj) => {
+    describe(`as target ${targetIsObj ? 'object' : 'element'}`, () => {
+      test('initialization and destruction', () => {
+        const target = getTarget();
+        const [beforeInitSnapshot, beforeInitSnapshotFn] = domSnapshot();
+        const [elements, destroy] = createStructureSetupElementsProxy(
+          targetIsObj ? { target } : target
+        );
+
+        assertCorrectDOMStructure(elements, target);
+
+        destroy();
+
+        expect(beforeInitSnapshot).toBe(beforeInitSnapshotFn());
+      });
+
+      test('cloning', () => {
+        const target = getTarget();
+        const [beforeInitSnapshot, beforeInitSnapshotFn] = domSnapshot();
+        const [elements, destroy] = createStructureSetupElementsProxy(
+          targetIsObj ? { target } : target
+        );
+        const clonedHorizontalSlot = document.createElement('div');
+        const clonedVerticalSlot = document.createElement('div');
+
+        const [beforeCloneHorizontalSnapshot, beforeCloneHorizontalSnapshotFn] =
+          domSnapshot(clonedHorizontalSlot);
+        const [beforeCloneVerticalSnapshot, beforeCloneVerticalSnapshotFn] =
+          domSnapshot(clonedVerticalSlot);
+
+        const clonedHorizontal = elements._horizontal._clone();
+        const clonedVertical = elements._vertical._clone();
+
+        clonedHorizontalSlot.append(clonedHorizontal._scrollbar);
+        clonedVerticalSlot.append(clonedVertical._scrollbar);
+
+        target.append(clonedHorizontalSlot);
+        target.append(clonedVerticalSlot);
+
+        assertCorrectDOMStructure(elements, target);
+        assertCorrectDOMStructure(
+          elements,
+          (isHorizontal) => (isHorizontal ? clonedHorizontalSlot : clonedVerticalSlot),
+          (structures, isHorizontal) => {
+            const clonedStructure = isHorizontal ? clonedHorizontal : clonedVertical;
+            return structures.find(
+              (structure) => structure._scrollbar === clonedStructure._scrollbar
+            )!;
+          }
+        );
+
+        destroy();
+
+        // destroy cleans up clones as well
+        expect(beforeCloneHorizontalSnapshot).toBe(beforeCloneHorizontalSnapshotFn());
+        expect(beforeCloneVerticalSnapshot).toBe(beforeCloneVerticalSnapshotFn());
+
+        clonedHorizontalSlot.remove();
+        clonedVerticalSlot.remove();
+
+        expect(beforeInitSnapshot).toBe(beforeInitSnapshotFn());
+      });
+    });
+  });
+
+  describe('addRemoveClass', () => {
+    test('add & remove classes to both axis', () => {
+      const target = getTarget();
+      const [elements] = createStructureSetupElementsProxy(target);
+
+      const horizontalStructures = elements._horizontal._scrollbarStructures;
+      const verticalStructures = elements._vertical._scrollbarStructures;
+      const className = 'aksjhdkasjd';
+
+      // clones before have the class
+      elements._horizontal._clone();
+      elements._vertical._clone();
+
+      elements._scrollbarsAddRemoveClass(className, true);
+
+      // clones after do not have the class
+      elements._horizontal._clone();
+      elements._vertical._clone();
+
+      horizontalStructures.forEach(({ _scrollbar }, i, arr) => {
+        if (i === arr.length - 1) {
+          expect(_scrollbar.classList.contains(className)).toBe(false);
+        } else {
+          expect(_scrollbar.classList.contains(className)).toBe(true);
+        }
+      });
+      verticalStructures.forEach(({ _scrollbar }, i, arr) => {
+        if (i === arr.length - 1) {
+          expect(_scrollbar.classList.contains(className)).toBe(false);
+        } else {
+          expect(_scrollbar.classList.contains(className)).toBe(true);
+        }
+      });
+
+      elements._scrollbarsAddRemoveClass(className);
+
+      horizontalStructures.forEach(({ _scrollbar }) => {
+        expect(_scrollbar.classList.contains(className)).toBe(false);
+      });
+      verticalStructures.forEach(({ _scrollbar }) => {
+        expect(_scrollbar.classList.contains(className)).toBe(false);
+      });
+    });
+
+    test('add & remove classes to individual axis', () => {
+      const target = getTarget();
+      const [elements] = createStructureSetupElementsProxy(target);
+
+      const horizontalStructures = elements._horizontal._scrollbarStructures;
+      const verticalStructures = elements._vertical._scrollbarStructures;
+      const classNameHorizontal = 'hhhhhhhhh12sdsdf';
+      const classNameVertical = 'vvvvvvv12sdsdf';
+
+      // clones before have the class
+      elements._horizontal._clone();
+      elements._vertical._clone();
+
+      elements._scrollbarsAddRemoveClass(classNameHorizontal, true, true);
+      elements._scrollbarsAddRemoveClass(classNameVertical, true, false);
+
+      // clones after do not have the class
+      elements._horizontal._clone();
+      elements._vertical._clone();
+
+      horizontalStructures.forEach(({ _scrollbar }, i, arr) => {
+        if (i === arr.length - 1) {
+          expect(_scrollbar.classList.contains(classNameHorizontal)).toBe(false);
+          expect(_scrollbar.classList.contains(classNameVertical)).toBe(false);
+        } else {
+          expect(_scrollbar.classList.contains(classNameHorizontal)).toBe(true);
+          expect(_scrollbar.classList.contains(classNameVertical)).toBe(false);
+        }
+      });
+      verticalStructures.forEach(({ _scrollbar }, i, arr) => {
+        if (i === arr.length - 1) {
+          expect(_scrollbar.classList.contains(classNameHorizontal)).toBe(false);
+          expect(_scrollbar.classList.contains(classNameVertical)).toBe(false);
+        } else {
+          expect(_scrollbar.classList.contains(classNameHorizontal)).toBe(false);
+          expect(_scrollbar.classList.contains(classNameVertical)).toBe(true);
+        }
+      });
+
+      elements._scrollbarsAddRemoveClass(classNameHorizontal, false, true);
+      elements._scrollbarsAddRemoveClass(classNameVertical, false, false);
+
+      horizontalStructures.forEach(({ _scrollbar }) => {
+        expect(_scrollbar.classList.contains(classNameHorizontal)).toBe(false);
+        expect(_scrollbar.classList.contains(classNameVertical)).toBe(false);
+      });
+      verticalStructures.forEach(({ _scrollbar }) => {
+        expect(_scrollbar.classList.contains(classNameHorizontal)).toBe(false);
+        expect(_scrollbar.classList.contains(classNameVertical)).toBe(false);
+      });
+    });
+  });
+
+  test('initialization and destruction in custom slot', () => {
+    const target = getTarget();
+    const slotFn = jest.fn(() => document.body);
+    const [beforeInitSnapshot, beforeInitSnapshotFn] = domSnapshot();
+    const [elements, destroy, structureElements] = createStructureSetupElementsProxy({
+      target,
+      scrollbars: {
+        slot: slotFn,
+      },
+    });
+
+    expect(slotFn).toHaveBeenCalledTimes(1);
+    expect(slotFn).toHaveBeenCalledWith(
+      structureElements._target,
+      structureElements._host,
+      structureElements._viewport
+    );
+
+    assertCorrectDOMStructure(elements, document.body);
+
+    destroy();
+
+    expect(beforeInitSnapshot).toBe(beforeInitSnapshotFn());
+  });
+
+  test('handleStyle', () => {
+    const target = getTarget();
+    const [elements] = createStructureSetupElementsProxy(target);
+    const testHandleStyle = (scrollbarSetupElement: ScrollbarsSetupElement) => {
+      // before cloned elements have the style
+      scrollbarSetupElement._clone();
+
+      scrollbarSetupElement._handleStyle((structure) => {
+        const { _scrollbar } = structure;
+        return [_scrollbar, { width: '0px' }];
+      });
+      scrollbarSetupElement._handleStyle((structure) => {
+        const { _track } = structure;
+        return [_track, { width: '1px' }];
+      });
+      scrollbarSetupElement._handleStyle((structure) => {
+        const { _handle } = structure;
+        return [_handle, { width: '2px' }];
+      });
+
+      // before cloned elements don not have the style
+      scrollbarSetupElement._clone();
+
+      scrollbarSetupElement._scrollbarStructures.forEach(
+        ({ _scrollbar, _track, _handle }, i, arr) => {
+          if (i === arr.length - 1) {
+            expect(_scrollbar.style.width).not.toBe('0px');
+            expect(_track.style.width).not.toBe('1px');
+            expect(_handle.style.width).not.toBe('2px');
+          } else {
+            expect(_scrollbar.style.width).toBe('0px');
+            expect(_track.style.width).toBe('1px');
+            expect(_handle.style.width).toBe('2px');
+          }
+        }
+      );
+    };
+
+    testHandleStyle(elements._horizontal);
+    testHandleStyle(elements._vertical);
+  });
+
+  test('removes transitionless class', () => {
+    const target = getTarget();
+    const [elements] = createStructureSetupElementsProxy(target);
+    const testHasTransitionlessClass = (
+      setupElement: ScrollbarsSetupElement,
+      expected: boolean
+    ) => {
+      const { _scrollbar } = setupElement._scrollbarStructures[0];
+      expect(_scrollbar.classList.contains(classNamesScrollbarTransitionless)).toBe(expected);
+    };
+
+    testHasTransitionlessClass(elements._horizontal, true);
+    testHasTransitionlessClass(elements._vertical, true);
+
+    jest.runAllTimers();
+
+    testHasTransitionlessClass(elements._horizontal, false);
+    testHasTransitionlessClass(elements._vertical, false);
+  });
+});
@@ -1,6 +1,11 @@
 import { hasClass, is, isFunction, isHTMLElement } from 'support';
-import { dataAttributeHost } from 'classnames';
-import { InternalEnvironment } from 'environment';
+import {
+  dataAttributeHost,
+  classNamePadding,
+  classNameViewport,
+  classNameContent,
+} from 'classnames';
+import { getEnvironment, InternalEnvironment } from 'environment';
 import {
  createStructureSetupElements,
  StructureSetupElementsObj,
@@ -12,9 +17,8 @@ import type {
  InitializationTargetObject,
 } from 'initialization';

-const mockGetEnvironment = jest.fn();
 jest.mock('environment', () => ({
-  getEnvironment: jest.fn().mockImplementation(() => mockGetEnvironment()),
+  getEnvironment: jest.fn(),
 }));

 jest.mock('support/compatibility/apis', () => {
@@ -81,10 +85,10 @@ const clearBody = () => {

 const getElements = (targetType: TargetType) => {
  const target = getTarget(targetType);
-  const host = document.querySelector('[data-overlayscrollbars]')!;
-  const padding = document.querySelector('.os-padding')!;
-  const viewport = document.querySelector('.os-viewport')!;
-  const content = document.querySelector('.os-content')!;
+  const host = document.querySelector(`[${dataAttributeHost}]`)!;
+  const padding = document.querySelector(`.${classNamePadding}`)!;
+  const viewport = document.querySelector(`.${classNameViewport}`)!;
+  const content = document.querySelector(`.${classNameContent}`)!;

  return {
    target,
@@ -133,7 +137,9 @@ const assertCorrectDOMStructure = (targetType: TargetType, viewportIsTarget: boo
  }
 };

-const createStructureSetupProxy = (target: InitializationTarget): StructureSetupElementsProxy => {
+const createStructureSetupElementsProxy = (
+  target: InitializationTarget
+): StructureSetupElementsProxy => {
  const [elements, appendElements, destroy] = createStructureSetupElements(target);
  appendElements();
  return {
@@ -422,9 +428,15 @@ const envInitStrategyViewportIsTarget = {
  },
 };

-describe('structureSetup', () => {
+describe('structureSetup.elements', () => {
  afterEach(() => clearBody());

+  beforeEach(() => {
+    (getEnvironment as jest.Mock).mockImplementation(() =>
+      jest.requireActual('environment').getEnvironment()
+    );
+  });
+
  [
    envDefault,
    envNativeScrollbarStyling,
@@ -436,8 +448,8 @@ describe('structureSetup', () => {
  ].forEach((envWithName) => {
    const { env: currEnv, name } = envWithName;
    describe(`Environment: ${name}`, () => {
-      beforeAll(() => {
-        mockGetEnvironment.mockImplementation(() => currEnv);
+      beforeEach(() => {
+        (getEnvironment as jest.Mock).mockImplementation(() => currEnv);
      });

      (['element', 'textarea', 'body'] as TargetType[]).forEach((targetType) => {
@@ -447,7 +459,7 @@ describe('structureSetup', () => {
              const snapshot = fillBody(targetType);
              const [elements, destroy] = assertCorrectSetupElements(
                targetType,
-                createStructureSetupProxy(getTarget(targetType)),
+                createStructureSetupElementsProxy(getTarget(targetType)),
                currEnv
              );
              assertCorrectDOMStructure(targetType, elements._viewportIsTarget);
@@ -458,7 +470,7 @@ describe('structureSetup', () => {
              const snapshot = fillBody(targetType);
              const [elements, destroy] = assertCorrectSetupElements(
                targetType,
-                createStructureSetupProxy({ target: getTarget(targetType) }),
+                createStructureSetupElementsProxy({ target: getTarget(targetType) }),
                currEnv
              );
              assertCorrectDOMStructure(targetType, elements._viewportIsTarget);
@@ -476,7 +488,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -497,7 +509,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: () => document.querySelector<HTMLElement>('#host'),
@@ -518,7 +530,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -541,7 +553,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -564,7 +576,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: () => document.querySelector<HTMLElement>('#host'),
@@ -586,7 +598,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -608,7 +620,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -628,7 +640,7 @@ describe('structureSetup', () => {
                const snapshot = fillBody(targetType);
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      padding: false,
@@ -644,7 +656,7 @@ describe('structureSetup', () => {
                const snapshot = fillBody(targetType);
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      content: () => false,
@@ -662,7 +674,7 @@ describe('structureSetup', () => {
                const snapshot = fillBody(targetType);
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      padding: () => true,
@@ -678,7 +690,7 @@ describe('structureSetup', () => {
                const snapshot = fillBody(targetType);
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      content: true,
@@ -696,7 +708,7 @@ describe('structureSetup', () => {
                const snapshot = fillBody(targetType);
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      padding: false,
@@ -715,7 +727,7 @@ describe('structureSetup', () => {
                const snapshot = fillBody(targetType);
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      padding: true,
@@ -738,7 +750,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -761,7 +773,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -784,7 +796,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -807,7 +819,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -830,7 +842,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -852,7 +864,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -874,7 +886,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -896,7 +908,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -918,7 +930,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -941,7 +953,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -964,7 +976,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -986,7 +998,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: () => document.querySelector<HTMLElement>('#host'),
@@ -1008,7 +1020,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -1030,7 +1042,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -1052,7 +1064,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: document.querySelector<HTMLElement>('#host'),
@@ -1075,7 +1087,7 @@ describe('structureSetup', () => {
                );
                const [elements, destroy] = assertCorrectSetupElements(
                  targetType,
-                  createStructureSetupProxy({
+                  createStructureSetupElementsProxy({
                    target: getTarget(targetType),
                    elements: {
                      host: () => document.querySelector<HTMLElement>('#host'),
@@ -1095,4 +1107,50 @@ describe('structureSetup', () => {
      });
    });
  });
+
+  describe('focus', () => {
+    describe('shift tabindex to viewport', () => {
+      test('with pointerdown on body', () => {
+        const { elements } = createStructureSetupElementsProxy(document.body);
+        expect(elements._viewport.getAttribute('tabindex')).toBe('-1');
+        expect(document.activeElement).toBe(elements._viewport);
+
+        elements._documentElm.dispatchEvent(new Event('pointerdown'));
+
+        expect(elements._viewport.getAttribute('tabindex')).toBe(null);
+      });
+
+      test('with keydown on element', () => {
+        document.body.innerHTML = '<div tabindex="123"></div>';
+        const target = document.body.firstElementChild as HTMLElement;
+        target.focus();
+
+        const { elements } = createStructureSetupElementsProxy(target);
+        expect(elements._viewport.getAttribute('tabindex')).toBe('-1');
+        expect(document.activeElement).toBe(elements._viewport);
+
+        elements._documentElm.dispatchEvent(new Event('keydown'));
+
+        expect(elements._viewport.getAttribute('tabindex')).toBe(null);
+      });
+    });
+
+    test('shift tabindex back to original activeElement', () => {
+      document.body.innerHTML = '<input type="text" value="hi"></input>';
+      const input = document.querySelector('input') as HTMLInputElement;
+      const target = document.body;
+
+      input.focus();
+      const preInitFocus = document.activeElement;
+
+      const { elements } = createStructureSetupElementsProxy(target);
+
+      expect(preInitFocus).toBe(document.activeElement);
+
+      elements._documentElm.dispatchEvent(new Event('pointerdown'));
+      elements._documentElm.dispatchEvent(new Event('keydown'));
+
+      expect(preInitFocus).toBe(document.activeElement);
+    });
+  });
 });