Selective_Event_Removal_And_Value_Aggregation_User_Transformation.js

function transform(events) {
    const filterEventNames = [
        // Add list of event names that you want to filter out
		"game_load_time",
		"lobby_fps"
    ];

	//remove events whose name match those in above list
    const filteredEvents = events.filter(event => {
        const eventName = event.event;
        return !(eventName && filterEventNames.includes(eventName));
    });
	
	
	//remove events of a certain type if related property value does not satisfy pre-defined condition
	//in this example, if 'total_payment' for a 'spin' event is null or 0, then it would be removed.
	//Only non-null, non-zero 'spin' events would be considered
    const nonSpinAndSpinPayerEvents = filteredEvents.filter( event => {
        const eventName = event.event;
        // spin events
        if(eventName.toLowerCase().indexOf('spin') >= 0) {
            if(event.userProperties && event.userProperties.total_payments && event.userProperties.total_payments > 0) {
                return true;
            } else {
                return false;
            }
        } else {
            return true;
        }
    });
    
    
    //in the below example, aggregation of three attributes - 'bet_amount', 'win_amount' and 'no_of_spin'
	//for all 'spin_result' events in the batch is being performed and instead of N 'spin_result' events,
	//a single 'spin_result' event with cumulative values is being provided
    let spin_result_events = nonSpinAndSpinPayerEvents.filter(event => {
        return event.event == "spin_result";
    });
    let bet_amount = 0;
    let win_amount = 0;
    let no_of_spin = 0;
    
    // sum these props
    
    spin_result_events.forEach(spEvent => {
        bet_amount +=  spEvent.properties.bet_amount ?  spEvent.properties.bet_amount : 0;
        win_amount +=  spEvent.properties.win_amount ?  spEvent.properties.win_amount : 0;
        no_of_spin +=  spEvent.properties.no_of_spin ?  spEvent.properties.no_of_spin : 0;
    })
    
    
    
    // modify the first spin_result_event
    if(spin_result_events.length > 0) {
        spin_result_events[0].properties.bet_amount = bet_amount;
        spin_result_events[0].properties.win_amount = win_amount;
        spin_result_events[0].properties.no_of_spin = no_of_spin;
    }
    
    // other than spin event
    let otherEvents = nonSpinAndSpinPayerEvents.filter(event => {
        return event.event != "spin_result";
    });
    
    
    if(otherEvents.length === 0) {
        otherEvents = [];
    }
    
    // add a single spin event
    
    if(spin_result_events.length > 0) {
        otherEvents.push(spin_result_events[0]);
    }
    
    return nonSpinAndSpinPayerEvents;
}