flex-flow

This is a shorthand property of flex-direction and flex-wrap

You can achieve the same results using flex-direction and flex-wrap

.container {
  flex-flow: row  wrap ;
}

In the following example, you can see the usage of flex-flow: row wrap; where children items are wrapped.

<div class="container">
  <div>1 </div>
  <div>2 </div>
  <div>3 </div>
  <div>4</div>
  <div>5</div>
  <div>6 </div>
</div>

.container{
  display:flex;
  flex-flow: row wrap;

}