fallback to initials if the image is not loaded (#40)

documentation/_getting-started.pug

@@ -257,6 +257,18 @@ a(href='https://github.com/eliep/vue-avatar')
                   initials="AS"
                   :size="100">
                 </avatar>
+        tr
+          td
+            avatar(username='Luke Skywalker', src='./static/luke-skywalker.png', :size='100')
+          td
+            pre
+              code.language-html.
+                <!-- fallback to initials if image doesn't load -->
+                <avatar
+                  src="./static/luke-skywalker.png"
+                  username="Luke Skywalker"
+                  :size="100">
+                </avatar>
 
     h2 Default color
     p

src/Avatar.vue

@@ -1,5 +1,7 @@
 <template>
   <div class="vue-avatar--wrapper" :style="[style, customStyle]" aria-hidden="true">
+    <!-- this img is not displayed; it is used to detect failure-to-load of div background image -->
+    <img v-if="this.isImage" style="display: none" :src="this.src" @error="onImgError"></img>
     <span v-show="!this.isImage">{{ userInitial }}</span>
   </div>
 </template>
@@ -49,7 +51,8 @@ export default {
         '#F44336', '#FF4081', '#9C27B0', '#673AB7',
         '#3F51B5', '#2196F3', '#03A9F4', '#00BCD4', '#009688',
         '#4CAF50', '#8BC34A', '#CDDC39', /* '#FFEB3B' , */ '#FFC107',
-        '#FF9800', '#FF5722', '#795548', '#9E9E9E', '#607D8B']
+        '#FF9800', '#FF5722', '#795548', '#9E9E9E', '#607D8B'],
+      imgError: false
     }
   },
 
@@ -73,7 +76,7 @@ export default {
     },
 
     isImage () {
-      return Boolean(this.src)
+      return !this.imgError && Boolean(this.src)
     },
 
     style () {
@@ -136,6 +139,10 @@ export default {
       return initials
     },
 
+    onImgError (evt) {
+      this.imgError = true
+    },
+
     randomBackgroundColor (seed, colors) {
       return colors[seed % (colors.length)]
     },

test/unit/specs/Avatar.spec.js

@@ -51,5 +51,18 @@ describe('Avatar.vue', function () {
 
     var backgroundImage = wrapper.element.style.backgroundImage
     expect(backgroundImage).to.contain('path/to/img')
+    expect(wrapper.element.querySelector('.vue-avatar--wrapper > span').textContent).not.to.contain('HF')
+  })
+
+  it('should render initials if the \'src\' does not load', function () {
+    var username = 'Hubert-Félix'
+
+    const wrapper = mount(Avatar, { propsData: {
+      username: username,
+      src: 'path/to/img'
+    } })
+    wrapper.setData({ imgError: true })
+
+    expect(wrapper.element.querySelector('.vue-avatar--wrapper > span').textContent).to.contain('HF')
   })
 })