I am using Google Books API to receive a list of books, but sometimes some book entry does not have some keys/properties, e.g., Authors, or does not have a Thumbnail. Thus JavaScript says that the property im trying to access is undefined and my application stucks.

Example Json data example from a book search containing the keywork Java

Full link

https://www.googleapis.com/books/v1/volumes?q=java&callback=jQuery191020691258599981666_1377508821982&_=1377508821983

E.g., when Authors is missing

TypeError: row.volumeInfo.authors is undefined

I tryied two solutions suggested

if ( typeof (authors) != undefined){}

and

if('authors' in booksObject) {}

but non of them seems to work, since they never enter the loops even when this proerty exists.

This is where I call

function populateListview(books) {



//iterate each returned item

$.each(books.items, function(i, row) {



    //populate each row in the list

    var htmlString = '<li><a href=book_details.html?id=' + row.id + '><img src=';



    htmlString += row.volumeInfo.imageLinks.thumbnail + '';

    htmlString += 'class=ui-li-has-thumb/><h3>';

    //Check if authors exists in JSON

    htmlString += row.volumeInfo.title + '</h3><p>' + row.volumeInfo.authors[0] + '</p></a></li>';



    //If not add an undefined authors string in the authors 





    console.log(htmlString);



    //append new html to the list

    $('#book_list').append(htmlString);

});



$('#book_list').listview('refresh');

// refresh the list-view so new elements are added to the DOM

};