Marko support rerendering

app/marko/src/client/preview/render.js

@@ -2,34 +2,61 @@ import { document } from 'global';
 import { stripIndents } from 'common-tags';
 
 const rootEl = document.getElementById('root');
-let currLoadedComponent = null; // currently loaded marko widget!
+let activeComponent = null; // currently loaded marko component.
+let activeTemplate = null; // template for the currently loaded component.
 
 export default function renderMain({
   storyFn,
   selectedKind,
   selectedStory,
   showMain,
   showError,
+  parameters,
   // forceRender,
 }) {
-  const element = storyFn();
+  const config = storyFn();
 
-  // We need to unmount the existing set of components in the DOM node.
-  if (currLoadedComponent) {
-    currLoadedComponent.destroy();
-  }
-
-  if (!element || !element.out) {
+  if (!config || !(config.appendTo || config.component || parameters.component)) {
     showError({
-      title: `Expecting a Marko element from the story: "${selectedStory}" of "${selectedKind}".`,
+      title: `Expecting an object with a component property to be returned from the story: "${selectedStory}" of "${selectedKind}".`,
       description: stripIndents`
-        Did you forget to return the Marko element from the story?
-        Use "() => MyComp.renderSync({})" or "() => { return MyComp.renderSync({}); }" when defining the story.
+        Did you forget to return the component from the story?
+        Use "() => ({ component: MyComponent, input: { hello: 'world' } })" when defining the story.
       `,
     });
+
     return;
   }
+  if (config.appendTo) {
+    console.warn(
+      '@storybook/marko: returning a rendered component for a story is deprecated, return an object with `{ component, input }` instead.'
+    );
+
+    // The deprecated API always destroys the previous component instance.
+    if (activeComponent) {
+      activeComponent.destroy();
+    }
+
+    activeComponent = config.appendTo(rootEl).getComponent();
+  } else {
+    const template = config.component || parameters.component;
+
+    if (activeTemplate === template) {
+      // When rendering the same template with new input, we reuse the same instance.
+      activeComponent.input = config.input;
+      activeComponent.update();
+    } else {
+      if (activeComponent) {
+        activeComponent.destroy();
+      }
+
+      activeTemplate = template;
+      activeComponent = activeTemplate
+        .renderSync(config.input)
+        .appendTo(rootEl)
+        .getComponent();
+    }
+  }
 
   showMain();
-  currLoadedComponent = element.appendTo(rootEl).getComponent();
 }

docs/src/pages/guides/guide-marko/index.md

@@ -88,15 +88,18 @@ That'll load stories in `../stories/index.js`. You can choose where to place sto
 Now create a `../stories/index.js` file, and write your first story like this:
 
 ```js
-/** @jsx m */
-
-import m from 'marko';
 import { storiesOf } from '@storybook/marko';
 import Button from '../components/button/index.marko';
 
 storiesOf('Button', module)
-  .add('with text', () => Button.renderSync({ text: 'some text'}))
-  .add('with emoji', () => Button.renderSync({ text: '😀 😎 👍 💯'}));
+  .add('with text', () => ({
+    component: Button,
+    input: { text 'some text' }
+  }))
+  .add('with emoji', () => ({
+    component: Button,
+    input: { text '😀 😎 👍 💯' }
+  }));
 ```
 
 Each story is a single state of your component. In the above case, there are two stories for the demo button component:

examples/marko-cli/src/stories/addon-actions.stories.js

@@ -5,7 +5,13 @@ export default {
   title: 'Addons|Actions/Button',
   parameters: {
     component: Button,
+    options: {
+      panelPosition: 'right',
+    },
   },
 };
 
-export const Simple = () => Button.renderSync({ click: action('action logged!') });
+export const Simple = () => ({
+  component: Button,
+  input: { click: action('action logged!') },
+});

examples/marko-cli/src/stories/addon-knobs.stories.js

@@ -10,11 +10,9 @@ export default {
   },
 };
 
-export const Simple = () => {
-  const name = text('Name', 'John Doe');
-  const age = number('Age', 44);
-  return Hello.renderSync({
-    name,
-    age,
-  });
-};
+export const Simple = () => ({
+  input: {
+    name: text('Name', 'John Doe'),
+    age: number('Age', 44),
+  },
+});

examples/marko-cli/src/stories/clickcount.stories.js

@@ -2,10 +2,9 @@ import ClickCount from '../components/click-count/index.marko';
 
 export default {
   title: 'Main|ClickCount',
-
   parameters: {
     component: ClickCount,
   },
 };
 
-export const Simple = () => ClickCount.renderSync({});
+export const Simple = () => ({ component: ClickCount });

examples/marko-cli/src/stories/hello.stories.js

@@ -7,6 +7,6 @@ export default {
   },
 };
 
-export const Simple = () => Hello.renderSync({ name: 'abc', age: 20 });
+export const Simple = () => ({ input: { name: 'abc', age: 20 } });
 export const story2 = () => 'NOT A MARKO RENDER_RESULT';
 story2.story = { name: 'with ERROR!' };

examples/marko-cli/src/stories/stopwatch.stories.js

@@ -7,4 +7,4 @@ export default {
   },
 };
 
-export const Simple = () => StopWatch.renderSync({});
+export const Simple = () => ({ component: StopWatch });

examples/marko-cli/src/stories/welcome.stories.js

@@ -7,4 +7,4 @@ export default {
   },
 };
 
-export const welcome = () => Welcome.renderSync({});
+export const welcome = () => ({ component: Welcome });

lib/cli/generators/MARKO/template/stories/index.stories.js

@@ -1,4 +1,4 @@
 import { storiesOf } from '@storybook/marko';
 import Welcome from './components/welcome/index.marko';
 
-storiesOf('Welcome', module).add('welcome', () => Welcome.renderSync({}));
+storiesOf('Welcome', module).add('welcome', () => ({ component: Welcome }));