feat: create <Portal>

README.md

@@ -8,7 +8,7 @@ React standard library — must-have toolbox for any React project.
 
   - React [router](https://mailonline.github.io/libreact/en/routing.html), [sensors](https://mailonline.github.io/libreact/en/Sensors.html), [FaCC](https://mailonline.github.io/libreact/en/Introduction.html#facc)s, [render props](https://mailonline.github.io/libreact/en/Introduction.html#render-props), [HOC](https://mailonline.github.io/libreact/en/Introduction.html#hoc)s, [context](https://mailonline.github.io/libreact/en/Context.html) providers, [dummies](https://mailonline.github.io/libreact/en/Dummies.html), and [other goodies](https://mailonline.github.io/libreact/en/).
   - *Isomorphic* - all components work in browser and on server (and some in `react-native`).
-  - See [demos](https://mailonline.github.io/libreact/demos/), [docs](https://mailonline.github.io/libreact/en/), and NPM [package](https://www.npmjs.com/package/libreact/).
+  - See [__demos__](https://mailonline.github.io/libreact/demos/), [__docs__](https://mailonline.github.io/libreact/en/), and NPM [__package__](https://www.npmjs.com/package/libreact/).
 
 
 ## Installation

src/Portal/index.ts

@@ -0,0 +1,52 @@
+import {Component} from 'react';
+import {createPortal} from 'react-dom';
+import {isClient} from '../util';
+
+export interface IPortalProps {
+  children?: any;
+  el?: HTMLElement;
+}
+
+export interface IPortalState {
+}
+
+export class Portal extends Component<IPortalProps, IPortalState> {
+  el: HTMLElement = null;
+
+  constructor (props, context) {
+    super(props, context);
+
+    if (isClient && !props.el) {
+      this.createEl();
+    }
+  }
+
+  componentWillUpdate (props) {
+    if (props.el && !this.el) {
+      this.createEl();
+    }
+  }
+
+  componentWillUnmount () {
+    if (this.el) {
+      document.body.removeChild(this.el);
+    }
+
+    this.el = null;
+  }
+
+  createEl () {
+    this.el = document.createElement('div');
+    document.body.appendChild(this.el);
+  }
+
+  render () {
+    if (!isClient) {
+      return null;
+    }
+
+    const {el, children} = this.props;
+
+    return createPortal(children, el || this.el);
+  }
+}