From 5cb588a586567235ffa98e48b441c6c2deadf9cb Mon Sep 17 00:00:00 2001
From: Alicia Sykes <sykes.alicia@gmail.com>
Date: Mon, 13 Dec 2021 22:40:35 +0000
Subject: [PATCH] :art: Handle loading state for widgets

---
 src/components/Widgets/Weather.vue    |   3 +-
 src/components/Widgets/WidgetBase.vue | 190 ++++++++++++++++----------
 src/mixins/WidgetMixin.js             |  26 ++--
 3 files changed, 129 insertions(+), 90 deletions(-)

diff --git a/src/components/Widgets/Weather.vue b/src/components/Widgets/Weather.vue
index bc760e22..80ad02ee 100644
--- a/src/components/Widgets/Weather.vue
+++ b/src/components/Widgets/Weather.vue
@@ -1,6 +1,5 @@
 <template>
-<LoadingAnimation v-if="loading" class="loader" />
-<div v-else class="weather">
+<div class="weather">
   <!-- Icon + Temperature -->
   <div class="intro">
     <p class="temp">{{ temp }}</p>
diff --git a/src/components/Widgets/WidgetBase.vue b/src/components/Widgets/WidgetBase.vue
index 4fbc47e0..cc05970c 100644
--- a/src/components/Widgets/WidgetBase.vue
+++ b/src/components/Widgets/WidgetBase.vue
@@ -1,91 +1,115 @@
 <template>
-  <div class="widget-base">
+  <div :class="`widget-base ${ loading ? 'is-loading' : '' }`">
+    <!-- Update and Full-Page Action Buttons  -->
     <Button :click="update" class="action-btn update-btn" v-if="!error && !loading">
       <UpdateIcon />
     </Button>
     <Button :click="fullScreenWidget" class="action-btn open-btn" v-if="!error && !loading">
       <OpenIcon />
     </Button>
-    <div v-if="loading">Loading...</div>
-    <div v-else-if="error" class="widget-error">
+    <!-- Loading Spinner -->
+    <div v-if="loading" class="loading">
+      <LoadingAnimation v-if="loading" class="loader" />
+    </div>
+    <!-- Error Message Display -->
+    <div v-if="error" class="widget-error">
       <p class="error-msg">An error occurred, see the logs for more info.</p>
       <p class="error-output">{{ errorMsg }}</p>
     </div>
-    <Clock
-      v-else-if="widgetType === 'clock'"
-      :options="widgetOptions"
-      @error="handleError"
-      :ref="widgetRef"
-    />
-    <Weather
-      v-else-if="widgetType === 'weather'"
-      :options="widgetOptions"
-      @error="handleError"
-      :ref="widgetRef"
-    />
-    <WeatherForecast
-      v-else-if="widgetType === 'weather-forecast'"
-      :options="widgetOptions"
-      @error="handleError"
-      :ref="widgetRef"
-    />
-    <TflStatus
-      v-else-if="widgetType === 'tfl-status'"
-      :options="widgetOptions"
-      @error="handleError"
-      :ref="widgetRef"
-    />
-    <CryptoPriceChart
-      v-else-if="widgetType === 'crypto-price-chart'"
-      :options="widgetOptions"
-      @error="handleError"
-      :ref="widgetRef"
-    />
-    <CryptoWatchList
-      v-else-if="widgetType === 'crypto-watch-list'"
-      :options="widgetOptions"
-      @error="handleError"
-      :ref="widgetRef"
-    />
-    <XkcdComic
-      v-else-if="widgetType === 'xkcd-comic'"
-      :options="widgetOptions"
-      @error="handleError"
-      :ref="widgetRef"
-    />
-    <ExchangeRates
-      v-else-if="widgetType === 'exchange-rates'"
-      :options="widgetOptions"
-      @error="handleError"
-      :ref="widgetRef"
-    />
-    <StockPriceChart
-      v-else-if="widgetType === 'stock-price-chart'"
-      :options="widgetOptions"
-      @error="handleError"
-      :ref="widgetRef"
-    />
-    <Jokes
-      v-else-if="widgetType === 'joke'"
-      :options="widgetOptions"
-      @error="handleError"
-      :ref="widgetRef"
-    />
-    <IframeWidget
-      v-else-if="widgetType === 'iframe'"
-      :options="widgetOptions"
-      @error="handleError"
-      :ref="widgetRef"
-    />
+    <!-- Widget -->
+    <div v-else class="widget-wrap">
+      <Clock
+        v-if="widgetType === 'clock'"
+        :options="widgetOptions"
+        @loading="setLoaderState"
+        @error="handleError"
+        :ref="widgetRef"
+      />
+      <Weather
+        v-else-if="widgetType === 'weather'"
+        :options="widgetOptions"
+        @loading="setLoaderState"
+        @error="handleError"
+        :ref="widgetRef"
+      />
+      <WeatherForecast
+        v-else-if="widgetType === 'weather-forecast'"
+        :options="widgetOptions"
+        @loading="setLoaderState"
+        @error="handleError"
+        :ref="widgetRef"
+      />
+      <TflStatus
+        v-else-if="widgetType === 'tfl-status'"
+        :options="widgetOptions"
+        @loading="setLoaderState"
+        @error="handleError"
+        :ref="widgetRef"
+      />
+      <CryptoPriceChart
+        v-else-if="widgetType === 'crypto-price-chart'"
+        :options="widgetOptions"
+        @loading="setLoaderState"
+        @error="handleError"
+        :ref="widgetRef"
+      />
+      <CryptoWatchList
+        v-else-if="widgetType === 'crypto-watch-list'"
+        :options="widgetOptions"
+        @loading="setLoaderState"
+        @error="handleError"
+        :ref="widgetRef"
+      />
+      <XkcdComic
+        v-else-if="widgetType === 'xkcd-comic'"
+        :options="widgetOptions"
+        @loading="setLoaderState"
+        @error="handleError"
+        :ref="widgetRef"
+      />
+      <ExchangeRates
+        v-else-if="widgetType === 'exchange-rates'"
+        :options="widgetOptions"
+        @loading="setLoaderState"
+        @error="handleError"
+        :ref="widgetRef"
+      />
+      <StockPriceChart
+        v-else-if="widgetType === 'stock-price-chart'"
+        :options="widgetOptions"
+        @loading="setLoaderState"
+        @error="handleError"
+        :ref="widgetRef"
+      />
+      <Jokes
+        v-else-if="widgetType === 'joke'"
+        :options="widgetOptions"
+        @loading="setLoaderState"
+        @error="handleError"
+        :ref="widgetRef"
+      />
+      <IframeWidget
+        v-else-if="widgetType === 'iframe'"
+        :options="widgetOptions"
+        @loading="setLoaderState"
+        @error="handleError"
+        :ref="widgetRef"
+      />
+      <!-- No widget type specified -->
+      <div v-else>{{ handleError('No widget type was specified') }}</div>
+    </div>
   </div>
 </template>
 
 <script>
+// Import form elements, icons and utils
 import ErrorHandler from '@/utils/ErrorHandler';
 import Button from '@/components/FormElements/Button';
 import UpdateIcon from '@/assets/interface-icons/widget-update.svg';
 import OpenIcon from '@/assets/interface-icons/open-new-tab.svg';
+import LoadingAnimation from '@/assets/interface-icons/loader.svg';
 
+// Import available widgets
 import Clock from '@/components/Widgets/Clock.vue';
 import Weather from '@/components/Widgets/Weather.vue';
 import WeatherForecast from '@/components/Widgets/WeatherForecast.vue';
@@ -104,6 +128,7 @@ export default {
     Button,
     UpdateIcon,
     OpenIcon,
+    LoadingAnimation,
     Clock,
     Weather,
     WeatherForecast,
@@ -134,25 +159,33 @@ export default {
       }
       return this.widget.type.toLowerCase();
     },
-    /* Returns the users specified widget options, or empty object */
+    /* Returns users specified widget options, or empty object */
     widgetOptions() {
       return this.widget.options || {};
     },
+    /* A unique string to reference the widget by */
     widgetRef() {
       return `widget-${this.widgetType}-${this.index}`;
     },
   },
   methods: {
+    /* Calls update data method on widget */
     update() {
       this.$refs[this.widgetRef].update();
     },
+    /* Shows message when error occurred */
     handleError(msg) {
       this.error = true;
       this.errorMsg = msg;
     },
+    /* Opens current widget in full-page */
     fullScreenWidget() {
       this.$emit('navigateToSection');
     },
+    /* Toggles loading state */
+    setLoaderState(loading) {
+      this.loading = loading;
+    },
   },
 };
 </script>
@@ -162,6 +195,7 @@ export default {
 .widget-base {
   position: relative;
   padding-top: 0.75rem;
+  // Refresh and full-page action buttons
   button.action-btn  {
     height: 1rem;
     min-width: auto;
@@ -184,7 +218,7 @@ export default {
       right: 1.75rem;
     }
   }
-
+  // Error message output
   .widget-error {
     p.error-msg {
       color: var(--warning);
@@ -199,6 +233,20 @@ export default {
       margin: 0.5rem auto;
     }
   }
+  // Loading spinner
+  .loading {
+    margin: 0.2rem auto;
+    text-align: center;
+    svg.loader {
+      width: 100px;
+    }
+  }
+  // Hide widget contents while loading
+  &.is-loading {
+    .widget-wrap {
+      display: none;
+    }
+  }
 }
 
 </style>
diff --git a/src/mixins/WidgetMixin.js b/src/mixins/WidgetMixin.js
index 81377667..7488fbd3 100644
--- a/src/mixins/WidgetMixin.js
+++ b/src/mixins/WidgetMixin.js
@@ -1,49 +1,41 @@
+/**
+ * Mixin that all pre-built and custom widgets extend from.
+ * Manages loading state, error handling and data updates.
+ */
 import ProgressBar from 'rsup-progress';
 import ErrorHandler from '@/utils/ErrorHandler';
-import LoadingAnimation from '@/assets/interface-icons/loader.svg';
 
 const WidgetMixin = {
-  components: {
-    LoadingAnimation,
-  },
   props: {
-    /* The options prop is an object of settings for a given widget */
     options: {
       type: Object,
       default: {},
     },
   },
   data: () => ({
-    loading: true, // Indicates current loading status, to display spinner
     progress: new ProgressBar({ color: 'var(--progress-bar)' }),
   }),
   methods: {
-    /* Overridden by widget component. Re-fetches and renders any external data  *
-     * Called by parent component, and triggered either by user or time interval */
+    /* Re-fetches external data, called by parent. Usually overridden by widget */
     update() {
-      // eslint-disable-next-line no-console
-      console.log('No update method configured for this widget');
+      console.log('No update method configured for this widget'); // eslint-disable-line no-console
     },
-    /* Called when an error occurs */
+    /* Called when an error occurs. Logs to handler, and passes to parent component */
     error(msg, stackTrace) {
       ErrorHandler(msg, stackTrace);
       this.$emit('error', msg);
     },
     /* When a data request update starts, show loader */
     startLoading() {
-      this.loading = true;
+      this.$emit('loading', true);
       this.progress.start();
     },
     /* When a data request finishes, hide loader */
     finishLoading() {
-      this.loading = false;
+      this.$emit('loading', false);
       setTimeout(() => { this.progress.end(); }, 500);
     },
   },
-  mounted() {
-    // If the mounted function isn't overridden,then hide loader
-    this.loading = false;
-  },
 };
 
 export default WidgetMixin;