`new Function` for json reference

Question

I have JSON with references to other parts in that JSON file.

// the function I would like to be reviewed
function referenceToObject(json, reference){
    return (new Function(
            'json', 'return json' + reference
    ))(json);
}

// json
var example = {
    "target": "['first']['second']",
    "first": {
        second: 'hi'
    }
};

// execution
console.log(referenceToObject(example, example.target));

That function basically executes like this:

return json['one']['two'];

Is there a better way to extract the JSON reference? I'm able to change every bit of this code, as well as the JSON because we are reworking the front- and the backend. So, if you have ideas to improve the JSON instead of the Javascript that would also be great.

Answer 1

Assuming that you control over the value of the target attribute, I suggest to store the reference chain as a list of attribute names. Then you can easily resolve the reference without having to resort to eval-like meta-programming. A reduction would be ideal like you mentioned.

function referenceToObject(json, target)
{
	if (target === undefined)
		target = json.target;

	return target.reduce(referenceToObject.reductor, json);
}

referenceToObject.reductor = function(obj, attrib)
{
	return obj[attrib];
};


var example = {
	"target": ['first', 'second'],
	"first": {
		second: 'hi'
	}
};

console.log(referenceToObject(example));