creating an object in json format

Question

In my node (express) app, I want to send a json response back to the client. It would look something like this.

{"someTshirt": 
      {small : 'available'},
      {med : 'available'},
      {large : 'not available'}
 }

I'd reiterate through the sizes and append to the response set with its availability. How would I create this object to begin with in plain javascript within app.js? how would I add the 'someTshirtName' to the beginning of this object as well as appending each size's availability to it after the object has been created?

Answer 1

You can build your object like this:

var availability = {"someTshirt": 
    {
        'small': 'available',
        'med' : 'available',
        'large' : 'not available'
    }
};

Then you can access this object with:

availability.someTshirt.small
>>> 'available'
availability.someTshirt.large
>>> 'not available'

However I'd recommend you to use booleans instead of strings, which are easier to manipulate. You can still change the display string later:

var availability = {"someTshirt": 
    {
        'small': true,
        'med' : true,
        'large' : false
    }
};

if (availability.someTshirt.small) {
    console.log('available');
}
>>> 'available'

[edit] Response to the comment:

If you want to create your objects dynamically, you can do the following:

var availability = {};
availability.someTshirt = {};
availability.someTshirt.small = true;
availability.someTshirt.med = true;
availability.someTshirt.large = false;

if (availability.someTshirt.small) {
    console.log("available");
} else {
    console.log("not available");
}
>>> 'available'

availability.someTshirt.small = false;

if (availability.someTshirt.small) {
    console.log("available");
} else {
    console.log("not available");
}
>>> 'not available'

Answer 2

If you need to build your object based on JSON string returned to your code, you can use eval statement. for example you have a string variable sJsonResult containing your JSON response. Your code can go something like;

var sJsonResult = "{someTshirt: {small : 'available', med : 'available',large : 'not available'}}";

var o;

eval("o = " + sJsonResult);

alert(o.someTshirt.small);