feat: create focused interaction for buttons

Author: marcosmoura

src/components/MdButton/MdButton.vue

@@ -1,6 +1,7 @@
 <script>
   import MdComponent from 'core/MdComponent'
-  import ripple from 'core/mixins/ripple'
+  import MdFocused from 'core/mixins/MdFocused/MdFocused'
+  import MdRipple from 'core/mixins/MdRipple/MdRipple'
   import MdRouterLinkProps from 'core/MdRouterLinkProps'
   import MdButtonContent from './MdButtonContent'
 
@@ -9,7 +10,10 @@
     components: {
       MdButtonContent
     },
-    mixins: [ripple],
+    mixins: [
+      MdRipple,
+      MdFocused
+    ],
     props: {
       href: String,
       type: {
@@ -31,7 +35,8 @@
         class: [
           this.$mdActiveTheme,
           {
-            'md-ripple-off': !this.mdRipple
+            'md-ripple-off': !this.mdRipple,
+            'md-focused': this.mdHasFocus
           }
         ],
         attrs: {

src/components/MdList/MdListItem/MdListItemMixin.js

@@ -1,8 +1,8 @@
-import ripple from 'core/mixins/ripple'
+import MdRipple from 'core/mixins/MdRipple/MdRipple'
 import MdListItemContent from './MdListItemContent'
 
 export default {
-  mixins: [ripple],
+  mixins: [MdRipple],
   components: {
     MdListItemContent
   },

src/core/mixins/MdFocused/MdFocused.js

@@ -0,0 +1,79 @@
+import MdReactive from 'core/MdReactive'
+
+const eventTarget = document.body
+
+let supportsPassiveEvent = false
+
+let MdFocused = new MdReactive({
+  currentElement: null
+})
+
+function checkPassiveEventSupport () {
+  try {
+    var opts = Object.defineProperty({}, 'passive', {
+      get () {
+        supportsPassiveEvent = { passive: true }
+      }
+    })
+    window.addEventListener('test', null, opts)
+  } catch (e) {}
+}
+
+function setKeyboardInteraction ({ keyCode, target }) {
+  MdFocused.currentElement = target
+}
+
+function setMouseAndTouchInteraction (event) {
+  MdFocused.currentElement = null
+}
+
+function createKeyboardEvents () {
+  eventTarget.addEventListener('keyup', setKeyboardInteraction)
+}
+
+function createPointerEvents () {
+  eventTarget.addEventListener('pointerup', setMouseAndTouchInteraction)
+}
+
+function createMSPointerEvents () {
+  eventTarget.addEventListener('MSPointerUp', setMouseAndTouchInteraction)
+}
+
+function createMouseAndTouchEvents () {
+  eventTarget.addEventListener('mouseup', setMouseAndTouchInteraction)
+
+  if ('ontouchend' in window) {
+    eventTarget.addEventListener('touchend', setMouseAndTouchInteraction, supportsPassiveEvent)
+  }
+}
+
+function bindEvents () {
+  if (window.PointerEvent) {
+    createPointerEvents()
+  } else if (window.MSPointerEvent) {
+    createMSPointerEvents()
+  } else {
+    createMouseAndTouchEvents()
+  }
+
+  createKeyboardEvents()
+}
+
+checkPassiveEventSupport()
+bindEvents()
+
+export default {
+  data: () => ({
+    mdHasFocus: false
+  }),
+  computed: {
+    focusedElement () {
+      return MdFocused.currentElement
+    }
+  },
+  watch: {
+    focusedElement (el) {
+      this.mdHasFocus = el === this.$el
+    }
+  }
+}