From 801581beadc19613029696edbe343a3d9c0aef7d Mon Sep 17 00:00:00 2001
From: Haroen Viaene <hello@haroen.me>
Date: Wed, 30 Sep 2020 10:28:10 +0200
Subject: [PATCH] fix(panel): react to changes on initial render
 (algolia/vue-instantsearch#871)

you can see this when there's a query which is applied from the URL (sorry, not relevant in the storybook) which makes the `canRefine` (`ais-Panel--noRefinement`) different than the default (`true`)
---
 .../src/mixins/__tests__/panel.test.js        | 29 ++++++++++++-------
 .../vue-instantsearch/src/mixins/panel.js     | 23 ++++++++-------
 .../stories/Panel.stories.js                  |  8 +++++
 3 files changed, 39 insertions(+), 21 deletions(-)

diff --git a/packages/vue-instantsearch/src/mixins/__tests__/panel.test.js b/packages/vue-instantsearch/src/mixins/__tests__/panel.test.js
index 5042297d35..408e5dca48 100644
--- a/packages/vue-instantsearch/src/mixins/__tests__/panel.test.js
+++ b/packages/vue-instantsearch/src/mixins/__tests__/panel.test.js
@@ -108,16 +108,18 @@ describe('createPanelConsumerMixin', () => {
       attributeName: false,
     };
 
-    expect(emitter.$emit).toHaveBeenCalledTimes(0);
+    expect(emitter.$emit).toHaveBeenCalledTimes(1);
+    expect(emitter.$emit).toHaveBeenLastCalledWith(PANEL_CHANGE_EVENT, false);
 
     wrapper.vm.state = {
       attributeName: true,
     };
 
-    expect(emitter.$emit).toHaveBeenCalledTimes(1);
+    expect(emitter.$emit).toHaveBeenCalledTimes(2);
+    expect(emitter.$emit).toHaveBeenLastCalledWith(PANEL_CHANGE_EVENT, true);
   });
 
-  it('emits at least once when both values are set', () => {
+  it('emits once when both values are set', () => {
     const localVue = createLocalVue();
     const emitter = createFakeEmitter();
     const Test = createFakeComponent(localVue);
@@ -137,7 +139,8 @@ describe('createPanelConsumerMixin', () => {
       attributeName: false,
     };
 
-    expect(emitter.$emit).toHaveBeenCalledTimes(0);
+    expect(emitter.$emit).toHaveBeenCalledTimes(1);
+    expect(emitter.$emit).toHaveBeenLastCalledWith(PANEL_CHANGE_EVENT, false);
 
     wrapper.vm.state = {
       attributeName: false,
@@ -146,7 +149,7 @@ describe('createPanelConsumerMixin', () => {
     expect(emitter.$emit).toHaveBeenCalledTimes(1);
   });
 
-  it('do not emit when the previous value is not set', () => {
+  it('emits once on init of the component', () => {
     const localVue = createLocalVue();
     const emitter = createFakeEmitter();
     const Test = createFakeComponent(localVue);
@@ -166,7 +169,8 @@ describe('createPanelConsumerMixin', () => {
       attributeName: true,
     };
 
-    expect(emitter.$emit).not.toHaveBeenCalled();
+    expect(emitter.$emit).toHaveBeenCalledTimes(1);
+    expect(emitter.$emit).toHaveBeenLastCalledWith(PANEL_CHANGE_EVENT, true);
   });
 
   it('do not emit when the next value is not set', () => {
@@ -189,11 +193,12 @@ describe('createPanelConsumerMixin', () => {
       attributeName: true,
     };
 
-    expect(emitter.$emit).not.toHaveBeenCalled();
+    expect(emitter.$emit).toHaveBeenCalledTimes(1);
+    expect(emitter.$emit).toHaveBeenLastCalledWith(PANEL_CHANGE_EVENT, true);
 
     wrapper.vm.state = null;
 
-    expect(emitter.$emit).not.toHaveBeenCalled();
+    expect(emitter.$emit).toHaveBeenCalledTimes(1);
   });
 
   it('do not emit when the previous and next value are equal', () => {
@@ -216,18 +221,20 @@ describe('createPanelConsumerMixin', () => {
       attributeName: true,
     };
 
-    expect(emitter.$emit).not.toHaveBeenCalled();
+    expect(emitter.$emit).toHaveBeenCalledTimes(1);
+    expect(emitter.$emit).toHaveBeenLastCalledWith(PANEL_CHANGE_EVENT, true);
 
     wrapper.vm.state = {
       attributeName: false,
     };
 
-    expect(emitter.$emit).toHaveBeenCalledTimes(1);
+    expect(emitter.$emit).toHaveBeenCalledTimes(2);
+    expect(emitter.$emit).toHaveBeenLastCalledWith(PANEL_CHANGE_EVENT, false);
 
     wrapper.vm.state = {
       attributeName: false,
     };
 
-    expect(emitter.$emit).toHaveBeenCalledTimes(1);
+    expect(emitter.$emit).toHaveBeenCalledTimes(2);
   });
 });
diff --git a/packages/vue-instantsearch/src/mixins/panel.js b/packages/vue-instantsearch/src/mixins/panel.js
index 40464ea370..7c90c864a3 100644
--- a/packages/vue-instantsearch/src/mixins/panel.js
+++ b/packages/vue-instantsearch/src/mixins/panel.js
@@ -58,19 +58,22 @@ export const createPanelConsumerMixin = ({ mapStateToCanRefine }) => ({
     };
   },
   watch: {
-    state(nextState, previousState) {
-      if (!previousState || !nextState) {
-        return;
-      }
+    state: {
+      immediate: true,
+      handler(nextState, previousState) {
+        if (!nextState) {
+          return;
+        }
 
-      const previousCanRefine = mapStateToCanRefine(previousState);
-      const nextCanRefine = mapStateToCanRefine(nextState);
+        const previousCanRefine = mapStateToCanRefine(previousState || {});
+        const nextCanRefine = mapStateToCanRefine(nextState);
 
-      if (!this.hasAlreadyEmitted || previousCanRefine !== nextCanRefine) {
-        this.emitter.$emit(PANEL_CHANGE_EVENT, nextCanRefine);
+        if (!this.hasAlreadyEmitted || previousCanRefine !== nextCanRefine) {
+          this.emitter.$emit(PANEL_CHANGE_EVENT, nextCanRefine);
 
-        this.hasAlreadyEmitted = true;
-      }
+          this.hasAlreadyEmitted = true;
+        }
+      },
     },
   },
 });
diff --git a/packages/vue-instantsearch/stories/Panel.stories.js b/packages/vue-instantsearch/stories/Panel.stories.js
index b04a25bc06..e341cfd90b 100644
--- a/packages/vue-instantsearch/stories/Panel.stories.js
+++ b/packages/vue-instantsearch/stories/Panel.stories.js
@@ -4,6 +4,14 @@ import { previewWrapper } from './utils';
 storiesOf('ais-panel', module)
   .addDecorator(previewWrapper())
   .add('default', () => ({
+    template: `
+      <ais-panel>
+        <template slot="header">Brand</template>
+        <ais-refinement-list attribute="brand" />
+      </ais-panel>
+  `,
+  }))
+  .add('text content', () => ({
     template: `
       <ais-panel>
         This is the body of the Panel.