Transitions

Using CSS classes, it is possible to implement transitions for when the modal is opened or closed. By placing the following CSS somewhere in your project's styles, you can make the modal content fade in when it is opened and fade out when it is closed:

.ReactModal__Overlay {
    opacity: 0;
    transition: opacity 2000ms ease-in-out;
}

.ReactModal__Overlay--after-open{
    opacity: 1;
}

.ReactModal__Overlay--before-close{
    opacity: 0;
}

The above example will apply the fade transition globally, affecting all modals whose afterOpen and beforeClose classes have not been set via the className prop. To apply the transition to one modal only, you can change the above class names and pass an object to your modal's className prop as described in the previous section.

In order for the fade transition to work, you need to inform the <Modal /> about the transition time required for the animation.

Like this

<Modal closeTimeoutMS={2000} />

closeTimeoutMS is expressed in milliseconds.

The closeTimeoutMS value and the value used in CSS or style prop passed to <Modal /> needs to be the same.

Warning: if you are using React 16, the close transition works only if you use the isOpen prop to toggle the visibility of the modal.

Do not conditionally render the <Modal />.

Instead of this

{
  this.state.showModal &&
  <Modal
    closeTimeoutMS={200}
    isOpen
    contentLabel="modal"
    onRequestClose={() => this.toggleModal()}
  >
    <h2>Add modal content here</h2>
  </Modal>
}

Do this

{
  <Modal
    closeTimeoutMS={200}
    isOpen={this.state.showModal}
    contentLabel="modal"
    onRequestClose={() => this.toggleModal()}
  >
    <h2>Add modal content here</h2>
  </Modal>
}

React Modal has adopted the stable Portal API API as exposed in React 16.

And createProtal API from React 16 no longer allow developers to intervene the unmounting of the portal component.