add iframe demo

docs/src/main.js

@@ -3,6 +3,7 @@ import 'prismjs/components/prism-jsx.js'
 import 'prismjs/components/prism-typescript.js'
 import 'prismjs/components/prism-scss.js'
 import PortalVue from 'portal-vue'
+import iframeResize from 'iframe-resizer/js/iframeResizer'
 import App from '~/layouts/App'
 
 Prism.manual = true
@@ -20,6 +21,16 @@ export default function (Vue, { head }) {
   }
 
   Vue.use(PortalVue)
+
+  Vue.directive('resize', {
+    bind(el, { value = {} }) {
+      el.addEventListener('load', () => iframeResize(value, el))
+    },
+    unbind(el) {
+      el.iFrameResizer.removeListeners()
+    },
+  })
+
   Vue.component('Layout', App)
   Vue.component('Demo', () => import(/* webpackChunkName: "demo" */ '~/components/Demo'))
   Vue.component('LiveDemo', () => import(/* webpackChunkName: "live-demo" */ '~/components/LiveDemo'))