.append

.append( elements Array, reverse Boolean )

Appends element/s to an Element

.append doesn't create reliable(.parent/.View) connection between parent and children. To make connected append, use .has .has method

let Elem='Parent'.append([
    'Child'.init(),
    'Child2'.init()
]);
O.ready.then(b=>b.append(Elem));     //Append Elem to document.body

<div class="Parent">
    <div class="Child"></div>
    <div class="Child2"></div>
</div>

Reverse append

To append elements reverse ordered, set reverse true

let Elem='Parent'.append([
    'Child'.init(),
    'Child2'.init()
],true);
O.ready.then(b=>b.append(Elem));     //Append Elem to document.body

<div class="Parent">
    <div class="Child2"></div>
    <div class="Child"></div>
</div>