Is it possible to map only a portion of an array? (Array.map())
you could use the slice function before to map the array, it looks like you want to do some pagination there.
var fruits = ['Banana', 'Orange', 'Lemon', 'Apple', 'Mango'];
var citrus = fruits.slice(1, 3);
// fruits contains ['Banana', 'Orange', 'Lemon', 'Apple', 'Mango']
// citrus contains ['Orange','Lemon']The easiest way in my head is just to use a filter and map
const feed = [1,2,3,4,5,6,7,8,9,10,11]
feed.filter((item, index) => index < 5).map((filteredItem) => //do somthing with filtred item here//)
where 5 is just a number of items you want to get
Do not try to solve this problem with a hack in your mapping step.
Instead, slice() the list to the right length first before the mapping:
class Feed extends React.Component {
constructor(props) {
super(props)
this.handleShowMore = this.handleShowMore.bind(this)
this.state = {
items: ['Item A', 'Item B', 'Item C', 'Item D'],
showItems: 2
}
}
handleShowMore() {
this.setState({
showItems:
this.state.showItems >= this.state.items.length ?
this.state.showItems : this.state.showItems + 1
})
}
render() {
const items = this.state.items.slice(0, this.state.showItems).map(
(item) => <div>{item}</div>
)
return (
<div>
{items}
<button onClick={this.handleShowMore}>
Show more!
</button>
</div>
)
}
}
ReactDOM.render(
<Feed />,
document.getElementById('root')
)<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<div id='root'></div>