How do you loop inside React JSX?

Naveera A.

—October 21, 2022

The Problem

You have a set of elements, and you’d like to loop over them to generate a JSX partial.

In templating languages, you can write a for loop directly inside the template. For example, you can use the following code to loop over a list in Jinja:

Click to Copy

{% for i in range(11) %}
    <li>{{ i }}</li>
{% endfor %}

How can you do the same thing using JSX?

The Solution

Two ways you can loop inside JSX are using traditional loops or using the map() method.

Using Traditional Loops

If you have a set of elements, you can use normal JavaScript for, for of, and for in loops outside the return block.

Inside the return block, you can use the resulting array.

You can loop over an array and create JSX partials like so:

Click to Copy

import React from "react";

function App() {
  const seasons = ["Spring", "Summer", "Autumn", "Winter"];

  let seasonsList = [];

  seasons.forEach((season, index) => {
    seasonsList.push(<li key={index}>{season}</li>);
  });

  return (
    <div>
      <h2>Seasons of the year</h2>
      <ul>{seasonsList}</ul>
    </div>
  );
}

export default App;

Using the `map()` Method

You can use the map() method on an array to loop through the elements and create components, or generate JSX, inside the return block.

Click to Copy

import React from "react";

function App() {
  const seasons = ["Spring", "Summer", "Autumn", "Winter"];

  return (
    <div>
      <h2>Seasons of the year</h2>
      <ul>
        {seasons.map((season) => (
          <li key={season.id}>{season}</li>
        ))}
      </ul>
    </div>
  );
}

export default App;

Many developers prefer using map() to loop over arrays.

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How do you loop inside React JSX?

The Problem

The Solution

Using Traditional Loops

Using the `map()` Method

Further Reading

Unsnag Your Mobile Monitoring: Why Teams Are Switching to Sentry

How do you loop inside React JSX?

The SolutionThe Solution

Using Traditional LoopsUsing Traditional Loops

Using the map() MethodUsing the map() Method

Further ReadingFurther Reading

The Solution

Using Traditional Loops

Using the `map()` Method

Further Reading