ex.jsx

var rows = [];

for (var i=0; i<items.length; i+=2){
  rows.push(<div className="parent-row">
    <div className="parent-card">
      {items[i]}
    </div>
    <div className="parent-card">
      {items[i+1]}
    </div>
  </div>)
}

ex.less

.parent-row {
  display: flex;
  align-items: stretch;
}

.parent-card {
  flex: 1;
}