[Saxon-JS 2] Creating a JSON object

Hi,

Is there a quicker/cleaner way to create a JSON object and store it in
a variable than this?

        <xsl:variable name="js-statement" as="element()">
            <root statement="{{ subject:
SPARQLBuilder.SelectBuilder.var('child'), predicate:
SPARQLBuilder.SelectBuilder.var('{$predicate}'), object:
SPARQLBuilder.SelectBuilder.var('whatever') }}"/>
        </xsl:variable>
        <xsl:variable name="bgp"
select="ixsl:eval(string($js-statement/@statement))"/>

$bgp is later being used like this: