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30-seconds-of-code/snippets/MappedList.md
Angelos Chalaris fc726d85a6 Update MappedList.md
2018-10-17 10:13:33 +03:00

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### MappedList
Renders a list of elements from an array of data.
Use the value of the `isOrderedList` prop to conditionally render a `<ol>` or `<ul>` list.
Use `Array.prototype.map` to render every item in `data` as a `<li>` element and give it a `key`.
`data` can either be an array of objects with the `id` and `value` properties or an array of primitives.
Omit the `isOrderedList` prop to render a `<ul>` list by default.
```jsx
function MappedList({ isOrderedList, data }) {
const list = data.map((v, i) => (
<li key={v.id ? v.id : i}>{v.value ? v.value : v}</li>
));
return isOrderedList ? <ol>{list}</ol> : <ul>{list}</ul>;
}
```
```jsx
const names = ['John', 'Paul', 'Mary'];
ReactDOM.render(<MappedList data={names}/>, document.getElementById('root'));
const users = [ { id: 8, value: 'john' }, { id: 3, value: 'paul' }];
ReactDOM.render(
<MappedList data={users} isOrderedList />,
document.getElementById('root')
);
```
<!-- tags: array,functional -->
<!-- expertise: 1 -->