Added Episode 2

cassiozen · cassiozen · commit d7c1631c8022 · 2016-11-16T01:16:50.000-02:00
diff --git a/episode2/README.md b/episode2/README.md
@@ -0,0 +1,30 @@
+# Function as Child Components
+
+ReactCasts, episode 2.
+
+“Function as Child Component” is a pattern where the parent component accepts a function as child, instead of a nested React Node. This screencast shows how to create a FaCC and use it for making information available to wrapped components.
+
+Screencast video:
+https://www.youtube.com/watch?v=WE3XAt9P8Ek
+
+# Outline
+
+- What are FaCC
+- Example: hypothetical use cases
+- Basic structure of a function as child component
+- Example: Scroll Position FaCC
+- Example: Refactor and Possible effects with the Scroll Position FaCC
+
+# Build & Run Instructions
+
+1. To build and run the code in this directory, ensure you have [npm](https://www.npmjs.com) installed
+
+2. Install
+```
+npm install
+```
+
+3. Start the application
+```
+npm start
+```
diff --git a/episode2/package.json b/episode2/package.json
@@ -0,0 +1,18 @@
+{
+  "name": "scrollPosition",
+  "version": "0.1.0",
+  "private": true,
+  "devDependencies": {
+    "react-scripts": "0.6.1"
+  },
+  "dependencies": {
+    "react": "^15.3.2",
+    "react-dom": "^15.3.2"
+  },
+  "scripts": {
+    "start": "react-scripts start",
+    "build": "react-scripts build",
+    "test": "react-scripts test --env=jsdom",
+    "eject": "react-scripts eject"
+  }
+}
diff --git a/episode2/public/favicon.ico b/episode2/public/favicon.ico
diff --git a/episode2/public/index.html b/episode2/public/index.html
@@ -0,0 +1,31 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+    <link rel="shortcut icon" href="%PUBLIC_URL%/favicon.ico">
+    <!--
+      Notice the use of %PUBLIC_URL% in the tag above.
+      It will be replaced with the URL of the `public` folder during the build.
+      Only files inside the `public` folder can be referenced from the HTML.
+
+      Unlike "/favicon.ico" or "favico.ico", "%PUBLIC_URL%/favicon.ico" will
+      work correctly both with client-side routing and a non-root public URL.
+      Learn how to configure a non-root public URL by running `npm run build`.
+    -->
+    <title>React App</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <!--
+      This HTML file is a template.
+      If you open it directly in the browser, you will see an empty page.
+
+      You can add webfonts, meta tags, or analytics to this file.
+      The build step will place the bundled scripts into the <body> tag.
+
+      To begin the development, run `npm start`.
+      To create a production bundle, use `npm run build`.
+    -->
+  </body>
+</html>
diff --git a/episode2/src/App.css b/episode2/src/App.css
@@ -0,0 +1,11 @@
+h1 {
+  font-size: 120px;
+}
+
+.App {
+  margin: 50px;
+}
+
+.spacer {
+  height: 1000px;
+}
diff --git a/episode2/src/App.js b/episode2/src/App.js
@@ -0,0 +1,24 @@
+
+import React, { Component } from 'react';
+import ScrollPos from './faac/ScrollPos';
+import './App.css';
+
+class App extends Component {
+  render() {
+    return (
+      <div className="App">
+        <div className="spacer" />
+
+        <ScrollPos>
+          {
+            position => <h1>{'Awesome Text!!!'.substr(0,position*15)}</h1>
+          }
+        </ScrollPos>
+
+        <div className="spacer" />
+      </div>
+    );
+  }
+}
+
+export default App;
diff --git a/episode2/src/App.test.js b/episode2/src/App.test.js
@@ -0,0 +1,8 @@
+import React from 'react';
+import ReactDOM from 'react-dom';
+import App from './App';
+
+it('renders without crashing', () => {
+  const div = document.createElement('div');
+  ReactDOM.render(<App />, div);
+});
diff --git a/episode2/src/faac/ScrollPos.js b/episode2/src/faac/ScrollPos.js
@@ -0,0 +1,47 @@
+import React, { Component, PropTypes } from 'react';
+
+class ScrollPos extends Component {
+
+  static proptypes = {
+    children: PropTypes.func.isRequired,
+  }
+
+  state = {
+    position: null
+  }
+
+  componentDidMount() {
+    window.addEventListener('scroll', this.handleScroll);
+  }
+
+  componentWillUnmount() {
+    window.removeEventListener('scroll', this.handleScroll);
+  }
+
+  getBounds = (element) => {
+    if (this.bounds) return;
+    this.bounds = element && element.getBoundingClientRect();
+  }
+
+  handleScroll = (event) => {
+    const windowSize = window.innerHeight;
+    const scrollTop = event.srcElement.body.scrollTop;
+    const visibleSpace = windowSize + (this.bounds.bottom - this.bounds.top);
+    let visibleRatio = ((windowSize + scrollTop) - this.bounds.top + this.bounds.height)/visibleSpace;
+
+    if (visibleRatio < 0) visibleRatio = 0;
+    if (visibleRatio > 1) visibleRatio = 1;
+
+    this.setState({position: visibleRatio})
+  }
+
+  render() {
+    return (
+      <div ref={this.getBounds}>{
+        this.props.children(this.state.position)
+      }</div>
+    )
+  }
+}
+
+export default ScrollPos;
diff --git a/episode2/src/index.css b/episode2/src/index.css
@@ -0,0 +1,5 @@
+body {
+  margin: 0;
+  padding: 0;
+  font-family: sans-serif;
+}
diff --git a/episode2/src/index.js b/episode2/src/index.js
@@ -0,0 +1,9 @@
+import React from 'react';
+import ReactDOM from 'react-dom';
+import App from './App';
+import './index.css';
+
+ReactDOM.render(
+  <App />,
+  document.getElementById('root')
+);
