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Modal

The modal component provides a solid foundation for creating dialogs, popovers, lightboxes, or whatever else.

The component renders its children node in front of a backdrop component. The Modal offers important features:

  • 💄 Manages modal stacking when one-at-a-time just isn't enough.
  • 🔐 Creates a backdrop, for disabling interaction below the modal.
  • 🔐 It disables scrolling of the page content while open.
  • ♿️ It properly manages focus; moving to the modal content, and keeping it there until the modal is closed.
  • ♿️ Adds the appropriate ARIA roles automatically.
  • 📦 5 kB gzipped.

Terminology note. The term "modal" is sometimes used to mean "dialog", but this is a misnomer. A Modal window describes parts of a UI. An element is considered modal if it blocks interaction with the rest of the application.

If you are creating a modal dialog, you probably want to use the Dialog component rather than directly using Modal. Modal is a lower-level construct that is leveraged by the following components:

Simple modal

Click to get the full Modal experience!

Notice that you can disable the outline (often blue or gold) with the outline: 0 CSS property.

Transitions

The open/close state of the modal can be animated with a transition component. This component should respect the following conditions:

  • Be a direct child descendent of the modal.
  • Have an in prop. This corresponds to the open / close state.
  • Call the onEnter callback prop when the enter transition starts.
  • Call the onExited callback prop when the exit transition is completed. These two callbacks allow the modal to unmount the child content when closed and fully transitioned.

Modal has built-in support for react-transition-group.

Alternatively, you can use react-spring.

Performance

The content of the modal is lazily mounted into the DOM. It ensures that having many closed modals in your React tree won't slow down your page.

However, creating React elements has a cost too. Consider the following case:

<Modal open={false}>
  <table>
    <thead>
      <tr>
        <td>Dessert (100g serving)</td>
        <td>Calories</td>
        <td>Fat (g)</td>
      </tr>
    </thead>
    <tbody>
      {rows.map(row => (
        <tr key={row.id}>
          <th scope="row">
            {row.name}
          </th>
          <td>{row.calories}</td>
          <td>{row.fat}</TableCell>
        </tr>
      ))}
    </tbody>
  </table>
</Modal>

We create a lot of React elements that will never be mounted. It's wasteful 🐢. You can speed up the rendering by moving the modal body into its own component.

<Modal open={false}>
  <TableComponent />
</Modal>

This way, you take advantage of React render laziness evaluation. The TableComponent render method will only be evaluated when opening the modal.

Accessibility

  • Be sure to add aria-labelledby="id...", referencing the modal title, to the Modal. Additionally, you may give a description of your modal with the aria-describedby="id..." prop on the Modal.
<Modal
  aria-labelledby="modal-title"
  aria-describedby="modal-description"
>
  <h2 id="modal-title">
    My Title
  </h2>
  <p id="modal-description">
    My Description
  </p>
</Modal>

Server-side modal

React doesn't support the createPortal() API on the server. In order to see the modal, you need to disable the portal feature with the disablePortal prop: