fix(field): change FocusEvent to regular Event to support IE11

Author: Joren Broekema

packages/field/src/FocusMixin.js

@@ -82,30 +82,30 @@ export const FocusMixin = dedupeMixin(
         // focus
         this.__redispatchFocus = ev => {
           ev.stopPropagation();
-          this.dispatchEvent(new FocusEvent('focus'));
+          this.dispatchEvent(new Event('focus'));
         };
         this.inputElement.addEventListener('focus', this.__redispatchFocus);
 
         // blur
         this.__redispatchBlur = ev => {
           ev.stopPropagation();
-          this.dispatchEvent(new FocusEvent('blur'));
+          this.dispatchEvent(new Event('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.dispatchEvent(new Event('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.dispatchEvent(new Event('focusout', { bubbles: true, composed: true }));
         };
         this.inputElement.addEventListener('focusout', this.__redispatchFocusout);
       }

packages/field/test/FocusMixin.test.js

@@ -77,7 +77,7 @@ describe('FocusMixin', () => {
     `);
     setTimeout(() => el.focus());
     const focusEv = await oneEvent(el, 'focus');
-    expect(focusEv).to.be.instanceOf(FocusEvent);
+    expect(focusEv).to.be.instanceOf(Event);
     expect(focusEv.target).to.equal(el);
     expect(focusEv.bubbles).to.be.false;
     expect(focusEv.composed).to.be.false;
@@ -87,7 +87,7 @@ describe('FocusMixin', () => {
       el.blur();
     });
     const blurEv = await oneEvent(el, 'blur');
-    expect(blurEv).to.be.instanceOf(FocusEvent);
+    expect(blurEv).to.be.instanceOf(Event);
     expect(blurEv.target).to.equal(el);
     expect(blurEv.bubbles).to.be.false;
     expect(blurEv.composed).to.be.false;
@@ -99,7 +99,7 @@ describe('FocusMixin', () => {
     `);
     setTimeout(() => el.focus());
     const focusinEv = await oneEvent(el, 'focusin');
-    expect(focusinEv).to.be.instanceOf(FocusEvent);
+    expect(focusinEv).to.be.instanceOf(Event);
     expect(focusinEv.target).to.equal(el);
     expect(focusinEv.bubbles).to.be.true;
     expect(focusinEv.composed).to.be.true;
@@ -109,7 +109,7 @@ describe('FocusMixin', () => {
       el.blur();
     });
     const focusoutEv = await oneEvent(el, 'focusout');
-    expect(focusoutEv).to.be.instanceOf(FocusEvent);
+    expect(focusoutEv).to.be.instanceOf(Event);
     expect(focusoutEv.target).to.equal(el);
     expect(focusoutEv.bubbles).to.be.true;
     expect(focusoutEv.composed).to.be.true;