From be2037f8d36e04a34b9af0ad1e7c76baf7fd6c35 Mon Sep 17 00:00:00 2001
From: Igor <igor-dv@users.noreply.github.com>
Date: Tue, 20 Nov 2018 11:52:25 +0200
Subject: [PATCH] Merge pull request #4773 from
 storybooks/vue-knobs-optimize-on-force-render

Vue / Knobs - optimize on force render
---
 app/react/src/client/preview/render.js        |  2 +-
 app/vue/src/client/preview/render.js          | 41 ++++++++++++++-----
 .../addon-knobs.stories.storyshot             |  2 +-
 .../src/stories/addon-knobs.stories.js        | 30 ++++++++++----
 4 files changed, 55 insertions(+), 20 deletions(-)

diff --git a/app/react/src/client/preview/render.js b/app/react/src/client/preview/render.js
index 507e5868563..90dda3f2dba 100644
--- a/app/react/src/client/preview/render.js
+++ b/app/react/src/client/preview/render.js
@@ -46,7 +46,7 @@ export default function renderMain({
   }
 
   // We need to unmount the existing set of components in the DOM node.
-  // Otherwise, React may not recrease instances for every story run.
+  // Otherwise, React may not recreate instances for every story run.
   // This could leads to issues like below:
   //    https://github.com/storybooks/react-storybook/issues/81
   // But forceRender means that it's the same story, so we want too keep the state in that case.
diff --git a/app/vue/src/client/preview/render.js b/app/vue/src/client/preview/render.js
index f6a4dbf0918..7204bfccae6 100644
--- a/app/vue/src/client/preview/render.js
+++ b/app/vue/src/client/preview/render.js
@@ -1,12 +1,26 @@
 import { stripIndents } from 'common-tags';
 import Vue from 'vue';
 
-let app = null;
+let root = null;
 
-function renderRoot(options) {
-  if (app) app.$destroy();
+function getComponentProxy(component) {
+  return Object.entries(component.props || {})
+    .map(([name, def]) => ({ [name]: def.default }))
+    .reduce((wrap, prop) => ({ ...wrap, ...prop }), {});
+}
 
-  app = new Vue(options);
+function renderRoot(component, proxy) {
+  root = new Vue({
+    el: '#root',
+    beforeCreate() {
+      this.proxy = proxy;
+    },
+
+    render(h) {
+      const props = this.proxy;
+      return h('div', { attrs: { id: 'root' } }, [h(component, { props })]);
+    },
+  });
 }
 
 export default function render({
@@ -16,6 +30,7 @@ export default function render({
   showMain,
   showError,
   showException,
+  forceRender,
 }) {
   Vue.config.errorHandler = showException;
 
@@ -33,10 +48,16 @@ export default function render({
   }
 
   showMain();
-  renderRoot({
-    el: '#root',
-    render(h) {
-      return h('div', { attrs: { id: 'root' } }, [h(component)]);
-    },
-  });
+
+  const proxy = getComponentProxy(component);
+
+  // at component creation || refresh by HMR
+  if (!root || !forceRender) {
+    if (root) root.$destroy();
+
+    renderRoot(component, proxy);
+  } else {
+    root.proxy = proxy;
+    root.$forceUpdate();
+  }
 }
diff --git a/examples/vue-kitchen-sink/src/stories/__snapshots__/addon-knobs.stories.storyshot b/examples/vue-kitchen-sink/src/stories/__snapshots__/addon-knobs.stories.storyshot
index 13bf0ff02a6..e851776c1de 100644
--- a/examples/vue-kitchen-sink/src/stories/__snapshots__/addon-knobs.stories.storyshot
+++ b/examples/vue-kitchen-sink/src/stories/__snapshots__/addon-knobs.stories.storyshot
@@ -40,7 +40,7 @@ exports[`Storyshots Addon|Knobs All knobs 1`] = `
 
 exports[`Storyshots Addon|Knobs Simple 1`] = `
 <div>
-  I am John Doe and I'm 44 years old.
+  I am John Doe and I'm 40 years old.
 </div>
 `;
 
diff --git a/examples/vue-kitchen-sink/src/stories/addon-knobs.stories.js b/examples/vue-kitchen-sink/src/stories/addon-knobs.stories.js
index cf8a0a7d74e..60f64526596 100644
--- a/examples/vue-kitchen-sink/src/stories/addon-knobs.stories.js
+++ b/examples/vue-kitchen-sink/src/stories/addon-knobs.stories.js
@@ -12,17 +12,31 @@ import {
   button,
 } from '@storybook/addon-knobs';
 
+const logger = console;
+
 storiesOf('Addon|Knobs', module)
   .addDecorator(withKnobs)
-  .add('Simple', () => {
-    const name = text('Name', 'John Doe');
-    const age = number('Age', 44);
-    const content = `I am ${name} and I'm ${age} years old.`;
+  .add('Simple', () => ({
+    props: {
+      name: {
+        type: String,
+        default: text('Name', 'John Doe'),
+      },
+    },
 
-    return {
-      template: `<div>${content}</div>`,
-    };
-  })
+    template: `<div @click="age++">I am {{ name }} and I'm {{ age }} years old.</div>`,
+
+    data() {
+      return { age: 40 };
+    },
+
+    created() {
+      logger.log('created');
+    },
+    destroyed() {
+      logger.log('destroyed');
+    },
+  }))
   .add('All knobs', () => {
     const name = text('Name', 'Jane');
     const stock = number('Stock', 20, {