Cheking if variable is undefined

Question

So I want to check if a variable is undefined in node.js. So far I work like this:

if(typeof object.data.items[1] === 'undefined')
{
    break;  
}
else
{
    console.log("Defined");         
}

But it gives me this error:

"TypeError: Cannot read property 'data' of undefined".

Any ideas on how to bypass this error while still checking if it's undefined?

Answer 1

check both object and object.data is defined first.

if(object && object.data && typeof object.data.items[1] === 'undefined')
{
    break;  
}
else
{
    console.log("Defined");         
}

or

if(!object || !object.data || typeof object.data.items[1] === 'undefined')
    {
        break;  
    }
    else
    {
        console.log("Defined");         
    }