---
title: DataList
tags: array,beginner
---

Renders a list of elements from an array of primitives.

- Use the value of the `isOrdered` prop to conditionally render a `<ol>` or `<ul>` list.
- Use `Array.prototype.map` to render every item in `data` as a `<li>` element, give it a `key` produced from the concatenation of the its index and value.
- Omit the `isOrdered` prop to render a `<ul>` list by default.

```jsx
function DataList({ isOrdered, data }) {
  const list = data.map((val, i) => <li key={`${i}_${val}`}>{val}</li>);
  return isOrdered ? <ol>{list}</ol> : <ul>{list}</ul>;
}
```

```jsx
const names = ['John', 'Paul', 'Mary'];
ReactDOM.render(<DataList data={names} />, document.getElementById('root'));
ReactDOM.render(<DataList data={names} isOrdered />, document.getElementById('root'));
```
