Rendering Lists

You will often want to display multiple similar components from a collection of data. You can use the JavaScript array methods to manipulate an array of data. On this page, you’ll use filter() and map() with React to filter and transform your array of data into an array of components.

You will learn

How to render components from an array using JavaScript’s map()
How to render only specific components using JavaScript’s filter()
When and why to use React keys

Rendering data from arrays

Say that you have a list of content.

<ul>
  <li>Creola Katherine Johnson: mathematician</li>
  <li>Mario José Molina-Pasquel Henríquez: chemist</li>
  <li>Mohammad Abdus Salam: physicist</li>
  <li>Percy Lavon Julian: chemist</li>
  <li>Subrahmanyan Chandrasekhar: astrophysicist</li>
</ul>

The only difference among those list items is their contents, their data. You will often need to show several instances of the same component using different data when building interfaces: from lists of comments to galleries of profile images. In these situations, you can store that data in JavaScript objects and arrays and use methods like map() and filter() to render lists of components from them.

Here’s a short example of how to generate a list of items from an array:

Move the data into an array:

const people = [
  'Creola Katherine Johnson: mathematician',
  'Mario José Molina-Pasquel Henríquez: chemist',
  'Mohammad Abdus Salam: physicist',
  'Percy Lavon Julian: chemist',
  'Subrahmanyan Chandrasekhar: astrophysicist'
];

Map the people members into a new array of JSX nodes, listItems:

const listItems = people.map(person => <li>{person}</li>);

Return listItems from your component wrapped in a <ul>:

return <ul>{listItems}</ul>;

Here is the result: