How to vertically align Bootstrap v4 modal dialogs

Question

Vertically center modal dialogues in Bootstrap 4.

Note: The requirements below have been added to make it clear I am looking for a prop

Answer 1

Try this,

::ng-deep{
    .modal-body{
        padding: 0.25rem;
        width: 600px !important;
    }
    .modal-content {
        position: relative;
        display: flex;
        flex-direction: row;
        margin-top: auto;
        margin-bottom: auto;
        width: 600px !important;
      }
}