feat: use Scoped Elements

Co-authored-by: Alex Ghiu <Alex.Ghiu@ing.com>
Co-authored-by: Thijs Louisse <Thijs.Louisse@ing.com>

README.md

@@ -135,6 +135,100 @@ Check out our [coding guidelines](./docs/README.md) for more detailed informatio
 Lion Web Components are only as good as its contributions.
 Read our [contribution guide](./CONTRIBUTING.md) and feel free to enhance/improve Lion. We keep feature requests closed while we're not working on them.
 
+## Scoped elements
+
+The [CustomElementRegistry](https://developer.mozilla.org/en-US/docs/Web/API/CustomElementRegistry) provides methods for registering custom elements. One of the limitations of working with this global registry is that multiple versions of the same element cannot co-exist. This causes bottlenecks in software delivery that should be managed by the teams and complex build systems. [Scoped Custom Element Registries](https://github.com/w3c/webcomponents/issues/716) is a proposal that will solve the problem. Since this functionality won't be available (especially not cross browser) anytime soon, we've adopted [OpenWC's Scoped Elements](https://open-wc.org/scoped-element).
+
+Whenever a lion component uses composition (meaning it uses another lion component inside), we
+apply ScopedElementsMixin to make sure it uses the right version of this internal component.
+
+```js
+import { ScopedElementsMixin, LitElement, html } from '@lion/core';
+
+import { LionInput } from '@lion/input';
+import { LionButton } from '@lion/button';
+
+class MyElement extends ScopedElementsMixin(LitElement) {
+  static get scopedElements() {
+    return {
+      'lion-input': LionInput,
+      'lion-button': LionButton,
+    };
+  }
+
+  render() {
+    return html`
+      <lion-input label="Greeting" name="greeting" .modelValue=${'Hello world'}></lion-input>
+      <lion-button>Save</lion-button>
+    `;
+  }
+}
+```
+
+### Query selectors
+
+Since Scoped Elements changes tagnames under the hood, a tagname querySelector should be written
+like this:
+
+```js
+this.querySelector(getTagName('lion-input', this.constructor.scopedElements));
+```
+
+### CSS selectors
+
+Avoid tagname css selectors (we already avoid query selectors internally in lion, but just be aware
+that a selector like `lion-input {...}` will stop working ).
+
+### Edge cases
+
+Sometimes we need to render parts of a template to light dom for [accessibility](https://wicg.github.io/aom/explainer.html). For instance we render a node via lit-html that we append to the host element, so
+it gets slotted in the right position.
+In this case, we should also make sure that we also scope the rendered element.
+
+We can do this as follows:
+
+```js
+_myLightTemplate() {
+  return html`
+    This template may be overridden by a Subclasser.
+    Even I don't end up in shadow root, I need to be scoped to constructor.scopedElements as well.
+    <div>
+      <lion-button>True</lion-button>
+      <lion-input label="xyz"></lion-input>
+    </div>
+  `;
+}
+
+__getLightDomNode() {
+  const renderParent = document.createElement('div');
+  this.constructor.render(this._myLightTemplate(), renderParent, {
+    scopeName: this.localName,
+    eventContext: this,
+  });
+  // this node will be appended to the host
+  return renderParent.firstElementChild;
+}
+
+connectedCallback() {
+  super.connectedCallback();
+  this.appendChild(this.__getLightDomNode());
+}
+```
+
+In a less complex case, we might just want to add a child node to the dom.
+
+```js
+import { ScopedElementsMixin, LitElement, getScopedTagNamegetScopedTagName  } from '@lion/core';
+
+...
+
+__getLightDomNode() {
+  return document.createElement(getScopedTagName('lion-input', this.constructor.scopedElements));
+}
+```
+
+We encourage you to have a look at [OpenWC's Scoped elements](https://open-wc.org/scoped-elements).
+
 ## Contact
 
 Feel free to create a github issue for any feedback or questions you might have.

package.json

@@ -75,7 +75,7 @@
   "bundlesize": [
     {
       "path": "./bundlesize/dist/core/core-*.js",
-      "maxSize": "10 kB"
+      "maxSize": "11 kB"
     },
     {
       "path": "./bundlesize/dist/all/all-*.js",

packages/input-datepicker/package.json

@@ -44,7 +44,8 @@
     "@lion/input-date": "0.5.17",
     "@lion/localize": "0.8.9",
     "@lion/overlays": "0.12.3",
-    "@lion/validate": "0.7.1"
+    "@lion/validate": "0.7.1",
+    "@open-wc/scoped-elements": "^0.5.0"
   },
   "devDependencies": {
     "@open-wc/demoing-storybook": "^1.10.4",

packages/input-datepicker/src/LionInputDatepicker.js

@@ -1,14 +1,22 @@
-import '@lion/calendar/lion-calendar.js';
-import { html, ifDefined, render } from '@lion/core';
+import { LionCalendar } from '@lion/calendar/src/LionCalendar';
+import { html, ifDefined, ScopedElementsMixin } from '@lion/core';
 import { LionInputDate } from '@lion/input-date';
 import { OverlayMixin, withModalDialogConfig } from '@lion/overlays';
-import './lion-calendar-overlay-frame.js';
+import { LionCalendarOverlayFrame } from './LionCalendarOverlayFrame.js';
 
 /**
  * @customElement lion-input-datepicker
  * @extends {LionInputDate}
  */
-export class LionInputDatepicker extends OverlayMixin(LionInputDate) {
+export class LionInputDatepicker extends ScopedElementsMixin(OverlayMixin(LionInputDate)) {
+  static get scopedElements() {
+    return {
+      ...super.scopedElements,
+      'lion-calendar': LionCalendar,
+      'lion-calendar-overlay-frame': LionCalendarOverlayFrame,
+    };
+  }
+
   static get properties() {
     return {
       /**
@@ -47,7 +55,10 @@ export class LionInputDatepicker extends OverlayMixin(LionInputDate) {
       ...super.slots,
       [this._calendarInvokerSlot]: () => {
         const renderParent = document.createElement('div');
-        render(this._invokerTemplate(), renderParent);
+        this.constructor.render(this._invokerTemplate(), renderParent, {
+          scopeName: this.localName,
+          eventContext: this,
+        });
         return renderParent.firstElementChild;
       },
     };
@@ -207,7 +218,7 @@ export class LionInputDatepicker extends OverlayMixin(LionInputDate) {
     // When not opened (usually on init), it does not need to be rendered.
     // This would make first paint quicker
     return html`
-      <lion-calendar-overlay-frame>
+      <lion-calendar-overlay-frame class="calendar__overlay-frame">
         <span slot="heading">${this.calendarHeading}</span>
         ${this._calendarTemplate()}
       </lion-calendar-overlay-frame>
@@ -349,7 +360,7 @@ export class LionInputDatepicker extends OverlayMixin(LionInputDate) {
     if (this._cachedOverlayContentNode) {
       return this._cachedOverlayContentNode;
     }
-    this._cachedOverlayContentNode = this.shadowRoot.querySelector('lion-calendar-overlay-frame');
+    this._cachedOverlayContentNode = this.shadowRoot.querySelector('.calendar__overlay-frame');
     return this._cachedOverlayContentNode;
   }
 }

packages/select-rich/src/LionSelectRich.js

@@ -1,12 +1,20 @@
 import { ChoiceGroupMixin } from '@lion/choice-input';
-import { css, html, LitElement, SlotMixin } from '@lion/core';
+import {
+  css,
+  html,
+  LitElement,
+  SlotMixin,
+  ScopedElementsMixin,
+  getScopedTagName,
+} from '@lion/core';
 import { FormControlMixin, FormRegistrarMixin, InteractionStateMixin } from '@lion/field';
 import { formRegistrarManager } from '@lion/field/src/registration/formRegistrarManager.js';
 import { OverlayMixin, withDropdownConfig } from '@lion/overlays';
 import { ValidateMixin } from '@lion/validate';
-import '../lion-select-invoker.js';
 import './differentKeyNamesShimIE.js';
 
+import { LionSelectInvoker } from './LionSelectInvoker.js';
+
 function uuid() {
   return Math.random()
     .toString(36)
@@ -46,13 +54,22 @@ function isInView(container, element, partial = false) {
  * @customElement lion-select-rich
  * @extends {LitElement}
  */
-export class LionSelectRich extends ChoiceGroupMixin(
-  OverlayMixin(
-    FormRegistrarMixin(
-      InteractionStateMixin(ValidateMixin(FormControlMixin(SlotMixin(LitElement)))),
+export class LionSelectRich extends ScopedElementsMixin(
+  ChoiceGroupMixin(
+    OverlayMixin(
+      FormRegistrarMixin(
+        InteractionStateMixin(ValidateMixin(FormControlMixin(SlotMixin(LitElement)))),
+      ),
     ),
   ),
 ) {
+  static get scopedElements() {
+    return {
+      ...super.scopedElements,
+      'lion-select-invoker': LionSelectInvoker,
+    };
+  }
+
   static get properties() {
     return {
       disabled: {
@@ -94,7 +111,10 @@ export class LionSelectRich extends ChoiceGroupMixin(
   get slots() {
     return {
       ...super.slots,
-      invoker: () => document.createElement('lion-select-invoker'),
+      invoker: () =>
+        document.createElement(
+          getScopedTagName('lion-select-invoker', this.constructor.scopedElements),
+        ),
     };
   }
 

packages/select-rich/test/lion-select-rich.test.js

@@ -217,7 +217,7 @@ describe('lion-select-rich', () => {
       `);
 
       expect(el._invokerNode).to.exist;
-      expect(el._invokerNode.tagName).to.equal('LION-SELECT-INVOKER');
+      expect(el._invokerNode.tagName).to.include('LION-SELECT-INVOKER');
     });
 
     it('sets the first option as the selectedElement if no option is checked', async () => {

packages/switch/src/LionSwitch.js

@@ -1,10 +1,9 @@
-import { html, css } from '@lion/core';
+import { html, css, ScopedElementsMixin, getScopedTagName } from '@lion/core';
 import { LionField } from '@lion/field';
 import { ChoiceInputMixin } from '@lion/choice-input';
+import { LionSwitchButton } from './LionSwitchButton.js';
 
-import '../lion-switch-button.js';
-
-export class LionSwitch extends ChoiceInputMixin(LionField) {
+export class LionSwitch extends ScopedElementsMixin(ChoiceInputMixin(LionField)) {
   static get styles() {
     return [
       super.styles,
@@ -16,10 +15,20 @@ export class LionSwitch extends ChoiceInputMixin(LionField) {
     ];
   }
 
+  static get scopedElements() {
+    return {
+      ...super.scopedElements,
+      'lion-switch-button': LionSwitchButton,
+    };
+  }
+
   get slots() {
     return {
       ...super.slots,
-      input: () => document.createElement('lion-switch-button'),
+      input: () =>
+        document.createElement(
+          getScopedTagName('lion-switch-button', this.constructor.scopedElements),
+        ),
     };
   }
 

packages/validate/package.json

@@ -37,7 +37,8 @@
   ],
   "dependencies": {
     "@lion/core": "0.4.4",
-    "@lion/localize": "0.8.9"
+    "@lion/localize": "0.8.9",
+    "@open-wc/scoped-elements": "^0.5.0"
   },
   "devDependencies": {
     "@open-wc/demoing-storybook": "^1.10.4",

packages/validate/src/ValidateMixin.js

@@ -1,7 +1,8 @@
 /* eslint-disable class-methods-use-this, camelcase, no-param-reassign, max-classes-per-file */
 
-import { dedupeMixin, SlotMixin } from '@lion/core';
+import { dedupeMixin, SlotMixin, ScopedElementsMixin, getScopedTagName } from '@lion/core';
 import { localize } from '@lion/localize';
+import { LionValidationFeedback } from './LionValidationFeedback.js';
 import { ResultValidator } from './ResultValidator.js';
 import { Unparseable } from './Unparseable.js';
 import { AsyncQueue } from './utils/AsyncQueue.js';
@@ -24,7 +25,14 @@ function arrayDiff(array1 = [], array2 = []) {
 export const ValidateMixin = dedupeMixin(
   superclass =>
     // eslint-disable-next-line no-unused-vars, no-shadow
-    class ValidateMixin extends SyncUpdatableMixin(SlotMixin(superclass)) {
+    class ValidateMixin extends ScopedElementsMixin(SyncUpdatableMixin(SlotMixin(superclass))) {
+      static get scopedElements() {
+        return {
+          ...super.scopedElements,
+          'lion-validation-feedback': LionValidationFeedback,
+        };
+      }
+
       static get properties() {
         return {
           /**
@@ -108,7 +116,10 @@ export const ValidateMixin = dedupeMixin(
       get slots() {
         return {
           ...super.slots,
-          feedback: () => document.createElement('lion-validation-feedback'),
+          feedback: () =>
+            document.createElement(
+              getScopedTagName('lion-validation-feedback', this.constructor.scopedElements),
+            ),
         };
       }
 
@@ -181,18 +192,10 @@ export const ValidateMixin = dedupeMixin(
         localize.addEventListener('localeChanged', this._updateFeedbackComponent);
       }
 
-      /**
-       * Should be overridden by subclasses if a different validation-feedback component is used
-       */
-      async _loadFeedbackComponent() {
-        await import('../lion-validation-feedback.js');
-      }
-
       firstUpdated(changedProperties) {
         super.firstUpdated(changedProperties);
         this.__validateInitialized = true;
         this.validate();
-        this._loadFeedbackComponent();
       }
 
       updateSync(name, oldValue) {