I'm just starting with Arrays, Objects, and JSON - so hopefully there's just something simple I'm overlooking here. I'm encountering an error when attempting to add (push) a new item into my json object.

I'm encountering the following error: Result of expression 'library.push' [undefined] is not a function (towards the bottom of my code snippet).

// This is my JSON object generated from a database

var library = {

    Gold Rush : {

        foregrounds : [Slide 1,Slide 2,Slide 3],

        backgrounds : [1.jpg,,2.jpg]

    },

    California : {

        foregrounds : [Slide 1,Slide 2,Slide 3],

        backgrounds : [3.jpg,4.jpg,5.jpg]

    }

}



// These will be dynamically generated vars from editor

var title = Gold Rush;

var foregrounds = [Howdy,Slide 2];

var backgrounds = [1.jpg,];



function save () {



    // If title already exists, modify item

    if (library[title]) {

        // Replace values with new

        library[title].foregrounds = foregrounds;

        library[title].backgrounds = backgrounds;



        // Save to Database. Then on callback...

        document.write('Changes Saved to <b>'+title+'</b>');



    // If title does not exist, add new item

    else {

        // Format it for the JSON object

        var item = (''+title+' : {foregrounds : '+foregrounds+',backgrounds : '+backgrounds+'}');





        // THE PROBLEM SEEMS TO BE HERE??

        // Error: Result of expression 'library.push' [undefined] is not a function

        library.push(item);





        // Save to Database. Then on callback...

        document.write('Added: <b>'+title+'</b>');

    }

}



save();