---
title: StarRating
tags: visual,children,input,state,intermediate
---

Renders a star rating component.

- Define a component, called `Star` that will render each individual star with the appropriate appearance, based on the parent component's state.
- In the `StarRating` component, use the `React.useState()` hook to define the `rating` and `selection` state variables with the initial values of `props.rating` (or `0` if invalid or not supplied) and `0`.
- Create a method, `hoverOver`, that updates `selected` and `rating` according to the provided `event`.
- 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 `selection` to `0`, the `onClick` event to set the `rating` and the `onMouseOver` event to set `selection` to the `star-id` attribute of the `event.target` respectively.
- Finally, pass the appropriate values to each `<Star>` component (`starId` and `marked`).

```jsx
function Star({ marked, starId }) {
  return (
    <span star-id={starId} style={{ color: '#ff9933' }} role="button">
      {marked ? '\u2605' : '\u2606'}
    </span>
  );
}

function StarRating(props) {
  const [rating, setRating] = React.useState(typeof props.rating == 'number' ? props.rating : 0);
  const [selection, setSelection] = React.useState(0);
  const hoverOver = event => {
    let val = 0;
    if (event && event.target && event.target.getAttribute('star-id'))
      val = event.target.getAttribute('star-id');
    setSelection(val);
  };
  return (
    <div
      onMouseOut={() => hoverOver(null)}
      onClick={event => setRating(event.target.getAttribute('star-id') || rating)}
      onMouseOver={hoverOver}
    >
      {Array.from({ length: 5 }, (v, i) => (
        <Star
          starId={i + 1}
          key={`star_${i + 1} `}
          marked={selection ? selection >= i + 1 : rating >= i + 1}
        />
      ))}
    </div>
  );
}
```

```jsx
ReactDOM.render(<StarRating />, document.getElementById('root'));
ReactDOM.render(<StarRating rating={2} />, document.getElementById('root'));
```
