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up vote 0 down vote favorite

I filled up an array with some objects like this and printing it out with JSON.stringifty(obj, null, '\t');

gives me output like this:

[
    {
        "title": "here's the title"
    },
    {
        "description": "this is a description"
    }
]

now I am trying to get the data back from this array with objects inside. Using array.map like this:

var title = objArray.map(function(a) {return a.title;});

when I do:

console.log(title); //the output looks like this
,here's the title,,,

If I manually reach into the array like this

console.log(results[0]['title']); //the output is well formatted
here's the title

why is that and how can I get the map function to not add those additional commas to my returned value?

share|improve this question
2  
map() returns an array. If you try to output (e.g. via console.log()) an array, it is first implicitly joined, as though you'd done array.join(). The commas are a result of that implicit join. – Utkanos Jul 27 at 18:10
up vote 1 down vote accepted

Yes because your 2 elements in your array are :

{
    "title": "here's the title"
}

and 

{
    "description": "this is a description"
}

but they haven't the same properties : so when you try to display the property title in the second element, JS interpretor just return undefined

share|improve this answer
up vote 0 down vote

It will return a value for everything in the array so you will get these empty values in the resulting array for the objects that do not have a title. You can check for the value of title before returning the value in the map function though. e.g.:

if (a.title) return a.title;
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