Merge pull request #12 from 30-seconds/Chalarangelo-star-rating

Add StarRating

snippets/StarRating.md

@@ -0,0 +1,76 @@
+### StarRating
+
+Renders a star rating component.
+
+Use and IIFE to define a functional component, called `Star` that will render each individual star with the appropriate appearance, based on the parent component's `state` and return the class component `StarRating`.
+Use the value of the `rating` prop to determine if a valid rating is supplied and store it in `state.rating` (or `0` if invalid or not supplied).
+Initialize `state.selection` to `0`.
+Create two methods, `hoverOver` and `setRating`, that take an event as argument and update `state.selected` and `state.rating` according to it, bind them both to the component's context.
+In the `render()` method, create a `<div>` to wrap the `<Star>` components, which are created using `Array.prototype.map` on an array of 5 elements, created using `Array.from`, and handle the `onMouseLeave` event to set `state.selection` to `0`, the `onClick` event to set
+the `state.rating` and the `onMouseOver` event to set `state.selection` to the `star-id` attribute of the `event.target` respectively. 
+Finally, pass the appropriate values to each `<Star>` component (`starId` and `marked`).
+
+```jsx
+const StarRating = (function() {
+  function Star({ marked, starId }) {
+    return (
+      <span star-id={starId} style={{ color: '#ff9933' }} role='button'>
+        {marked ? '\u2605' : '\u2606'}
+      </span>
+    );
+  }
+
+  return class StarRating extends React.Component {
+    constructor(props) {
+      super(props);
+      this.state = {
+        rating: typeof props.rating == 'number' ? props.rating : 0,
+        selection: 0
+      };
+      this.hoverOver = this.hoverOver.bind(this);
+      this.hoverOut = this.hoverOver.bind(this, null);
+      this.handleClick = this.handleClick.bind(this);
+    }
+    hoverOver(event) {
+      let val = 0;
+      if (event && event.target && event.target.getAttribute('star-id'))
+        val = event.target.getAttribute('star-id');
+      this.setState(state => ({ selection: val }));
+    }
+    handleClick(event) {
+      const val = event.target.getAttribute('star-id') || this.state.rating;
+      this.setState(state => ({ rating: val }));
+    }
+    render() {
+      return (
+        <div
+          onMouseOut={this.hoverOut}
+          onClick={this.handleClick}
+          onMouseOver={this.hoverOver}
+        >
+          {Array.from({ length: 5 }, (v, i) => (
+            <Star
+              starId={i+1}
+              key={`star_${i+1} `}
+              marked={
+                this.state.selection
+                  ? this.state.selection >= i+1
+                  : this.state.rating >= i+1
+              }
+            />
+          ))}
+        </div>
+      );
+    }
+  };
+})();
+```
+
+```jsx
+ReactDOM.render(<StarRating/>, document.getElementById('root'));
+ReactDOM.render(<StarRating rating={2} />, document.getElementById('root'));
+```
+
+<!-- tags: visual,children,input,state,class -->
+
+<!-- expertise: 2 -->