fix(field): no delegate in FocusMixin; sync focused, redispatch events

packages/field/src/FocusMixin.js

@@ -1,52 +1,120 @@
-import { dedupeMixin, DelegateMixin } from '@lion/core';
+import { dedupeMixin } from '@lion/core';
 
 export const FocusMixin = dedupeMixin(
   superclass =>
     // eslint-disable-next-line no-unused-vars, max-len, no-shadow
-    class FocusMixin extends DelegateMixin(superclass) {
+    class FocusMixin extends superclass {
-      get delegations() {
+      static get properties() {
         return {
-          ...super.delegations,
+          focused: {
-          target: () => this.inputElement,
+            type: Boolean,
-          events: [...super.delegations.events, 'focus', 'blur'], // since these events don't bubble
+            reflect: true,
-          methods: [...super.delegations.methods, 'focus', 'blur'],
+          },
-          properties: [...super.delegations.properties, 'onfocus', 'onblur', 'autofocus'],
-          attributes: [...super.delegations.attributes, 'onfocus', 'onblur', 'autofocus'],
         };
       }
 
+      constructor() {
+        super();
+        this.focused = false;
+      }
+
       connectedCallback() {
+        if (super.connectedCallback) {
           super.connectedCallback();
-        this._onFocus = this._onFocus.bind(this);
+        }
-        this._onBlur = this._onBlur.bind(this);
+        this.__registerEventsForFocusMixin();
-        this.inputElement.addEventListener('focusin', this._onFocus);
-        this.inputElement.addEventListener('focusout', this._onBlur);
       }
 
       disconnectedCallback() {
+        if (super.disconnectedCallback) {
           super.disconnectedCallback();
-        this.inputElement.removeEventListener('focusin', this._onFocus);
+        }
-        this.inputElement.removeEventListener('focusout', this._onBlur);
+        this.__teardownEventsForFocusMixin();
+      }
+
+      focus() {
+        const native = this.inputElement;
+        if (native) {
+          native.focus();
+        }
+      }
+
+      blur() {
+        const native = this.inputElement;
+        if (native) {
+          native.blur();
+        }
+      }
+
+      updated(changedProperties) {
+        super.updated(changedProperties);
+        // 'state-focused' css classes are deprecated
+        if (changedProperties.has('focused')) {
+          this.classList[this.focused ? 'add' : 'remove']('state-focused');
+        }
       }
 
       /**
-       * Helper Function to easily check if the element is being focused
+       * Functions should be private
        *
-       * TODO: performance comparision vs
+       * @deprecated
-       *   return this.inputElement === document.activeElement;
        */
-      get focused() {
-        return this.classList.contains('state-focused');
-      }
-
       _onFocus() {
-        if (super._onFocus) super._onFocus();
+        if (super._onFocus) {
-        this.classList.add('state-focused');
+          super._onFocus();
+        }
+        this.focused = true;
       }
 
+      /**
+       * Functions should be private
+       *
+       * @deprecated
+       */
       _onBlur() {
-        if (super._onBlur) super._onBlur();
+        if (super._onBlur) {
-        this.classList.remove('state-focused');
+          super._onBlur();
+        }
+        this.focused = false;
+      }
+
+      __registerEventsForFocusMixin() {
+        // focus
+        this.__redispatchFocus = ev => {
+          ev.stopPropagation();
+          this.dispatchEvent(new FocusEvent('focus'));
+        };
+        this.inputElement.addEventListener('focus', this.__redispatchFocus);
+
+        // blur
+        this.__redispatchBlur = ev => {
+          ev.stopPropagation();
+          this.dispatchEvent(new FocusEvent('blur'));
+        };
+        this.inputElement.addEventListener('blur', this.__redispatchBlur);
+
+        // focusin
+        this.__redispatchFocusin = ev => {
+          ev.stopPropagation();
+          this._onFocus(ev);
+          this.dispatchEvent(new FocusEvent('focusin', { bubbles: true, composed: true }));
+        };
+        this.inputElement.addEventListener('focusin', this.__redispatchFocusin);
+
+        // focusout
+        this.__redispatchFocusout = ev => {
+          ev.stopPropagation();
+          this._onBlur();
+          this.dispatchEvent(new FocusEvent('focusout', { bubbles: true, composed: true }));
+        };
+        this.inputElement.addEventListener('focusout', this.__redispatchFocusout);
+      }
+
+      __teardownEventsForFocusMixin() {
+        this.inputElement.removeEventListener('focus', this.__redispatchFocus);
+        this.inputElement.removeEventListener('blur', this.__redispatchBlur);
+        this.inputElement.removeEventListener('focusin', this.__redispatchFocusin);
+        this.inputElement.removeEventListener('focusout', this.__redispatchFocusout);
       }
     },
 );

packages/field/test/FocusMixin.test.js

@@ -0,0 +1,117 @@
+import { expect, fixture, html, defineCE, unsafeStatic, oneEvent } from '@open-wc/testing';
+
+import { LitElement } from '@lion/core';
+import { FocusMixin } from '../src/FocusMixin.js';
+
+describe('FocusMixin', () => {
+  let tag;
+
+  before(async () => {
+    const tagString = defineCE(
+      class extends FocusMixin(LitElement) {
+        render() {
+          return html`
+            <slot name="input"></slot>
+          `;
+        }
+
+        get inputElement() {
+          return this.querySelector('input');
+        }
+      },
+    );
+
+    tag = unsafeStatic(tagString);
+  });
+
+  it('focuses/blurs the underlaying native element on .focus()/.blur()', async () => {
+    const el = await fixture(html`
+      <${tag}><input slot="input"></${tag}>
+    `);
+    el.focus();
+    expect(document.activeElement === el.inputElement).to.be.true;
+    el.blur();
+    expect(document.activeElement === el.inputElement).to.be.false;
+  });
+
+  it('has an attribute focused when focused', async () => {
+    const el = await fixture(html`
+      <${tag}><input slot="input"></${tag}>
+    `);
+    el.focus();
+    await el.updateComplete;
+    expect(el.hasAttribute('focused')).to.be.true;
+
+    el.blur();
+    await el.updateComplete;
+    expect(el.hasAttribute('focused')).to.be.false;
+  });
+
+  it('becomes focused/blurred if the native element gets focused/blurred', async () => {
+    const el = await fixture(html`
+      <${tag}><input slot="input"></${tag}>
+    `);
+    expect(el.focused).to.be.false;
+    el.inputElement.focus();
+    expect(el.focused).to.be.true;
+    el.inputElement.blur();
+    expect(el.focused).to.be.false;
+  });
+
+  it('has a deprecated "state-focused" css class when focused', async () => {
+    const el = await fixture(html`
+      <${tag}><input slot="input"></${tag}>
+    `);
+    el.focus();
+    await el.updateComplete;
+    expect(el.classList.contains('state-focused')).to.be.true;
+
+    el.blur();
+    await el.updateComplete;
+    expect(el.classList.contains('state-focused')).to.be.false;
+  });
+
+  it('dispatches [focus, blur] events', async () => {
+    const el = await fixture(html`
+      <${tag}><input slot="input"></${tag}>
+    `);
+    setTimeout(() => el.focus());
+    const focusEv = await oneEvent(el, 'focus');
+    expect(focusEv).to.be.instanceOf(FocusEvent);
+    expect(focusEv.target).to.equal(el);
+    expect(focusEv.bubbles).to.be.false;
+    expect(focusEv.composed).to.be.false;
+
+    setTimeout(() => {
+      el.focus();
+      el.blur();
+    });
+    const blurEv = await oneEvent(el, 'blur');
+    expect(blurEv).to.be.instanceOf(FocusEvent);
+    expect(blurEv.target).to.equal(el);
+    expect(blurEv.bubbles).to.be.false;
+    expect(blurEv.composed).to.be.false;
+  });
+
+  it('dispatches [focusin, focusout] events with { bubbles: true, composed: true }', async () => {
+    const el = await fixture(html`
+      <${tag}><input slot="input"></${tag}>
+    `);
+    setTimeout(() => el.focus());
+    const focusinEv = await oneEvent(el, 'focusin');
+    expect(focusinEv).to.be.instanceOf(FocusEvent);
+    expect(focusinEv.target).to.equal(el);
+    expect(focusinEv.bubbles).to.be.true;
+    expect(focusinEv.composed).to.be.true;
+
+    setTimeout(() => {
+      el.focus();
+      el.blur();
+    });
+    const focusoutEv = await oneEvent(el, 'focusout');
+    expect(focusoutEv).to.be.instanceOf(FocusEvent);
+    expect(focusoutEv.target).to.equal(el);
+    expect(focusoutEv.bubbles).to.be.true;
+    expect(focusoutEv.composed).to.be.true;
+  });
+});

packages/field/test/lion-field.test.js

@@ -68,24 +68,6 @@ describe('<lion-field>', () => {
     expect(cbBlurNativeInput.callCount).to.equal(2);
   });
 
-  it('has class "state-focused" if focused', async () => {
-    const el = await fixture(`<${tagString}>${inputSlotString}</${tagString}>`);
-    expect(el.classList.contains('state-focused')).to.equal(false, 'no state-focused initially');
-    await triggerFocusFor(el.inputElement);
-    expect(el.classList.contains('state-focused')).to.equal(true, 'state-focused after focus()');
-    await triggerBlurFor(el.inputElement);
-    expect(el.classList.contains('state-focused')).to.equal(false, 'no state-focused after blur()');
-  });
-
-  it('offers simple getter "this.focused" returning true/false for the current focus state', async () => {
-    const el = await fixture(`<${tagString}>${inputSlotString}</${tagString}>`);
-    expect(el.focused).to.equal(false);
-    await triggerFocusFor(el);
-    expect(el.focused).to.equal(true);
-    await triggerBlurFor(el);
-    expect(el.focused).to.equal(false);
-  });
-
   it('can be disabled via attribute', async () => {
     const elDisabled = await fixture(`<${tagString} disabled>${inputSlotString}</${tagString}>`);
     expect(elDisabled.disabled).to.equal(true);
@@ -395,12 +377,6 @@ describe('<lion-field>', () => {
   });
 
   describe(`Delegation${nameSuffix}`, () => {
-    it('delegates attribute autofocus', async () => {
-      const el = await fixture(`<${tagString} autofocus>${inputSlotString}</${tagString}>`);
-      expect(el.hasAttribute('autofocus')).to.be.false;
-      expect(el.inputElement.hasAttribute('autofocus')).to.be.true;
-    });
-
     it('delegates property value', async () => {
       const el = await fixture(`<${tagString}>${inputSlotString}</${tagString}>`);
       expect(el.inputElement.value).to.equal('');
@@ -426,23 +402,6 @@ describe('<lion-field>', () => {
       }
     });
 
-    it('delegates property onfocus', async () => {
-      const el = await fixture(`<${tagString}>${inputSlotString}</${tagString}>`);
-      const cbFocusHost = sinon.spy();
-      el.onfocus = cbFocusHost;
-      await triggerFocusFor(el.inputElement);
-      expect(cbFocusHost.callCount).to.equal(1);
-    });
-
-    it('delegates property onblur', async () => {
-      const el = await fixture(`<${tagString}>${inputSlotString}</${tagString}>`);
-      const cbBlurHost = sinon.spy();
-      el.onblur = cbBlurHost;
-      await triggerFocusFor(el.inputElement);
-      await triggerBlurFor(el.inputElement);
-      expect(cbBlurHost.callCount).to.equal(1);
-    });
-
     it('delegates property selectionStart and selectionEnd', async () => {
       const el = await fixture(html`
         <${tag}