You could use it this way:
<xe:outline id="outline4">
<xe:this.treeNodes>
<xe:repeatTreeNode var="val">
<xe:this.children>
<xe:basicLeafNode>
<xe:this.submitValue>#{javascript:return val[1]}]]>xe:this.submitValue>
<xe:this.label>#{javascript:return val[0]}]]>xe:this.label>
xe:basicLeafNode>
xe:this.children>
<xe:this.value>#{javascript:return [
["Home","home"],
["Domino","domino"],
["OneUI","oneui"]
];}]]>xe:this.value>
xe:repeatTreeNode>
xe:this.treeNodes>
<xp:eventHandler event="onItemClick" submit="true"
refreshMode="partial" refreshId="panel5">
<xp:this.action>#{javascript:viewScope.dynamicValue = context.getSubmittedValue()}]]>xp:this.action>
xp:eventHandler>
xe:outline>