Attribute Customisation:Script basedvalue Set using Javascript for Mutliple values as Columnids

Hello Team,

I used Provider as "HTTP Filtered Value Set" with below configuration,
URL: https://xxx.com:9443/ccm/oslc/contexts/_D4CKIMJyEeSJxvvhbOuJ2A/workitems?oslc_cm.query=dc:type="com.rtc.configuration.workitemtype.type.delivery" &oslc_cm.properties=dc:identifier,dc:title
rowxpath="//Collection/ChangeRequest";
columnxpath="./title|./Identifier";
columnids="summary|id";
label format=${0}:${1}

Results comes: M.2.4: 10201

Same i am trying using the Scriptbased value set (Javascript).But not sure how to get the both the values,

dojo.provide("net.example.scripted.oslc.wiids.ValueSetProvider");

dojo.require("com.ibm.team.workitem.api.common.connectors.HttpConnectorParameters");

(function() {
    dojo.declare("net.example.scripted.oslc.wiids.ValueSetProvider", null, {

        getValueSet: function(attributeId, workItem, context){

        var params= new com.ibm.team.workitem.api.common.connectors.HttpConnectorParameters();
        params.url="https://xxxx.com:9443/ccm/oslc/contexts/_D4CKIMJyEeSJxvvhbOuJ2A/workitems?oslc_cm.query=dc:type=%22com.rtc.configuration.workitemtype.type.delivery%22&oslc_cm.properties=dc:identifier,dc:title";
        params.xpath="//Collection/ChangeRequest";
        params.columnXpaths=["./identifier|./title"];
        params.columnIds=["deliveryNo|deliverySum"];
        params.ignoreInvalidCertificates=true;
        params.useOAuth=true;

        var connector= context.getDataConnector("HttpConnector");
        var values= connector.get(params);
        var result= [];

        while(values.hasNext()){
            var entry= values.next();
            var wid= entry.getById("deliveryno");  ===> This only works if column id is only ONE not for the above         
            var wsummary=entry.getById("deliverySum")
            //Concat both wid + wsummary and assign to wid
            result.push(wid);
        }

        return result;
    }
   });
})();


Can you let me know how to fetch the multiple values in the Reponse?