Prevent getting error if variable is undefined?

Question

I need to replace imagesrc with the value stored in this object. However when I run:

if(data['results'][res]['entities']['media']["0"]["media_url"]) {
    imagesrc = data['results'][res]['entities']['media']["0"]["media_url"];
}

I get the error:

Cannot read property '0' of undefined

How can I run my condition so that I don't get errors if something is undefined?

Answer 1

if (data['results'][res]['entities']['media']["0"] == undefined
    || data['results'][res]['entities']['media']["0"] == null) {

    ...
}

Answer 2

you can place your code inside a try catch block and examin error message.