Iterating through an object array in js: skip when undefined

Question

I'd like to iterate trough a javascript array (nested objects: based on collection+Json) and collect data from its objects. But if the data of an object isn't available, skip it and go to the next object, resp. continue the iteration. Currently, this error appears if the data isn't available in the according object: Uncaught TypeError: Cannot read property 'hk5' of undefined

How can I check first, if the data (hereafter hk5) is available?

Iterating through all "data-objects"

for (var i = 0; i < data.collection.items.length; i++) {
    var data = data.collection.items[i].data[2].value.packet_data_field.application_data_params.hk5;
    console.log(belaMode);
}

Thanks!

Answer 1

for (var i = 0; i < data.collection.items.length; i++) {
    if(typeof(data.collection.items[i].data[2].value.packet_data_field.application_data_params) != 'undefined'){
    var data = data.collection.items[i].data[2].value.packet_data_field.application_data_params.hk5;
    }
    console.log(belaMode);
}

Answer 2

if(data.collection.items[i].data[2].value.packet_data_field.application_data_params!=undefined){}