From 947d253dad7f08a677aba095463e988624e60eee Mon Sep 17 00:00:00 2001
From: Troy Morehouse <troymore@nbnet.nb.ca>
Date: Wed, 19 Jul 2017 20:38:14 -0300
Subject: [PATCH] feat(collapse): apply bootstrap classes during transition
 stages (issue #565) (#707)

* Update collapse.vue

* Update toggle.js

* Update collapse.spec.js

* [collapse] document show, shown, hide, hidden events

* Update meta.json
---
 __tests__/components/collapse.spec.js |  38 ++++++---
 docs/components/collapse/meta.json    |  16 ++++
 lib/components/collapse.vue           | 116 ++++++++++++++------------
 lib/directives/toggle.js              |   7 ++
 4 files changed, 112 insertions(+), 65 deletions(-)

diff --git a/__tests__/components/collapse.spec.js b/__tests__/components/collapse.spec.js
index e3e143425fc..76202f8cbbb 100755
--- a/__tests__/components/collapse.spec.js
+++ b/__tests__/components/collapse.spec.js
@@ -1,4 +1,4 @@
-import {loadFixture, testVM, setData, nextTick} from '../helpers';
+import {loadFixture, testVM, setData, nextTick, sleep} from '../helpers';
 
 describe('collapse', async() => {
     beforeEach(loadFixture('collapse'));
@@ -139,32 +139,44 @@ describe('collapse', async() => {
         const btn3 = $refs.accordion_3_btn
         const col3 = $refs.accordion_3
 
-        expect(col1.$el.classList.contains('show')).toBe(true)
         expect(btn1.$el.getAttribute('aria-expanded')).toBe('true')
-        expect(col2.$el.classList.contains('show')).toBe(false)
         expect(btn2.$el.getAttribute('aria-expanded')).toBe('false')
-        expect(col3.$el.classList.contains('show')).toBe(false)
         expect(btn3.$el.getAttribute('aria-expanded')).toBe('false')
 
-        btn2.$el.click();
+        expect(col1.show).toBe(true)
+        expect(col2.show).toBe(false)
+        expect(col3.show).toBe(false)
+
+        // Open pane 2 and close others
+        btn2.$el.click()
         await nextTick()
-        
-        expect(col1.$el.classList.contains('show')).toBe(false)
+
         expect(btn1.$el.getAttribute('aria-expanded')).toBe('false')
-        expect(col2.$el.classList.contains('show')).toBe(true)
         expect(btn2.$el.getAttribute('aria-expanded')).toBe('true')
-        expect(col3.$el.classList.contains('show')).toBe(false)
         expect(btn3.$el.getAttribute('aria-expanded')).toBe('false')
 
-        btn2.$el.click();
+        await nextTick()
+
+        expect(col1.show).toBe(false)
+        expect(col2.show).toBe(true)
+        expect(col3.show).toBe(false)
+
+        await nextTick()
+
+        // Close all accordion panes
+        btn2.$el.click()
         await nextTick()
         
-        expect(col1.$el.classList.contains('show')).toBe(false)
         expect(btn1.$el.getAttribute('aria-expanded')).toBe('false')
-        expect(col2.$el.classList.contains('show')).toBe(false)
         expect(btn2.$el.getAttribute('aria-expanded')).toBe('false')
-        expect(col3.$el.classList.contains('show')).toBe(false)
         expect(btn3.$el.getAttribute('aria-expanded')).toBe('false')
+
+        await nextTick()
+
+        expect(col1.show).toBe(false)
+        expect(col2.show).toBe(false)
+        expect(col3.show).toBe(false)
+
     })
 
 });
diff --git a/docs/components/collapse/meta.json b/docs/components/collapse/meta.json
index 95574b49d53..0b7c336151c 100755
--- a/docs/components/collapse/meta.json
+++ b/docs/components/collapse/meta.json
@@ -2,6 +2,22 @@
   "title": "Collapse",
   "component": "bCollapse",
   "events": [
+    {
+      "event": "show",
+      "description": "emitted when collaspe has started to open"
+    },
+    {
+      "event": "shown",
+      "description": "emitted when collaspe has finised opening"
+    },
+    {
+      "event": "hide",
+      "description": "emitted when collaspe has started to close"
+    },
+    {
+      "event": "hidden",
+      "description": "emitted when collaspe has finished closing"
+    },
     {
       "event": "collapse::toggle",
       "description": "toggles visible state of collaspe when this event emits on $root",
diff --git a/lib/components/collapse.vue b/lib/components/collapse.vue
index 366d4a741b9..f319560fea2 100755
--- a/lib/components/collapse.vue
+++ b/lib/components/collapse.vue
@@ -1,10 +1,15 @@
 <template>
     <transition
-            @enter="enter"
-            @after-enter="clearHeight"
-            @leave="leave"
-            @after-leave="clearHeight"
-            name="collapse"
+            enter-class=""
+            enter-active-class="collapsing"
+            enter-to-class=""
+            leave-class=""
+            leave-active-class="collapsing"
+            leave-to-class=""
+            @enter="onEnter"
+            @after-enter="onAfterEnter"
+            @leave="onLeave"
+            @after-leave="onAfterLeave"
     >
         <div :id="id || null" :class="classObject" v-show="show">
             <slot></slot>
@@ -12,13 +17,6 @@
     </transition>
 </template>
 
-<style scoped>
-    .collapse-enter-active, .collapse-leave-active {
-        transition: all .35s ease;
-        overflow: hidden;
-    }
-</style>
-
 <script>
     import { listenOnRootMixin } from '../mixins';
 
@@ -26,38 +24,23 @@
         mixins: [listenOnRootMixin],
         data() {
             return {
-                show: this.visible
+                show: this.visible,
+                transitioning: false
             };
         },
-        computed: {
-            classObject() {
-                return {
-                    'navbar-collapse': this.isNav,
-                    show: this.show
-                };
-            }
-        },
         model: {
             prop: 'visible',
             event: 'input'
         },
-        watch: {
-            visible(newVal) {
-                if (newVal !== this.show) {
-                    this.show = newVal;
-                    this.emitState();
-                }
-            },
-        },
         props: {
-            isNav: {
-                type: Boolean,
-                default: false
-            },
             id: {
                 type: String,
                 required: true
             },
+            isNav: {
+                type: Boolean,
+                default: false
+            },
             accordion: {
                 type: String,
                 default: null
@@ -67,33 +50,60 @@
                 default: false
             }
         },
+        watch: {
+            visible(newVal) {
+                if (newVal !== this.show) {
+                    this.show = newVal;
+                }
+            },
+            show(newVal, oldVal) {
+                if (newVal !== oldVal) {
+                    this.emitState();
+                }
+            }
+        },
+        computed: {
+            classObject() {
+                return {
+                    'navbar-collapse': this.isNav,
+                    'collapse': !this.transitioning,
+                    'show': this.show && !this.transitioning
+                };
+            }
+        },
         methods: {
             toggle() {
                 this.show = !this.show;
-                this.emitState();
             },
-            enter(el) {
-                el.style.height = 'auto';
-                const realHeight = getComputedStyle(el).height;
-                el.style.height = '0px';
-
-                /* eslint-disable no-unused-expressions */
-                el.offsetHeight; // Force repaint
-
-                el.style.height = realHeight;
+            onEnter(el) {
+                el.style.height = 0;
+                this.reflow(el);
+                el.style.height = el.scrollHeight + 'px';
+                this.transitioning = true;
+                this.$emit('show');
             },
-            leave(el) {
+            onAfterEnter(el) {
+                el.style.height = null;
+                this.transitioning = false;
+                this.$emit('shown');
+            },
+            onLeave(el) {
                 el.style.height = 'auto';
-                const realHeight = getComputedStyle(el).height;
-                el.style.height = realHeight;
-
-                /* eslint-disable no-unused-expressions */
-                el.offsetHeight; // Force repaint
-
-                el.style.height = '0px';
+                el.style.display = 'block';
+                el.style.height = el.getBoundingClientRect().height + 'px';
+                this.reflow(el);
+                this.transitioning = true;
+                el.style.height = 0;
+                this.$emit('hide');
             },
-            clearHeight(el) {
+            onAfterLeave(el) {
                 el.style.height = null;
+                this.transitioning = false;
+                this.$emit('hidden');
+            },
+            reflow(el) {
+                /* eslint-disable no-unused-expressions */
+                el.offsetHeight; // Force repaint
             },
             emitState() {
                 this.$emit('input', this.show);
@@ -114,10 +124,12 @@
                     return;
                 }
                 if (openedId === this.id) {
+                    // Open this collapse if not shown
                     if (!this.show) {
                         this.toggle();
                     }
                 } else {
+                    // Close this collapse if shown
                     if (this.show) {
                         this.toggle();
                     }
diff --git a/lib/directives/toggle.js b/lib/directives/toggle.js
index 1bb575a673a..5b9a19ae03d 100755
--- a/lib/directives/toggle.js
+++ b/lib/directives/toggle.js
@@ -28,7 +28,14 @@ export default {
             // Toggle state hadnler, stored on element
             el[BVT] = function toggleDirectiveHandler(id, state) {
                 if (targets.indexOf(id) !== -1) {
+                    // Set aria-expanded state
                     el.setAttribute('aria-expanded', state ? 'true' : 'false');
+                    // Set 'collapsed' class state
+                    if (state) {
+                        el.classList.remove('collapsed');
+                    } else {
+                        el.classList.add('collapsed');
+                    }
                 }
             };