JSON parse error on undefined object

I'm currently attempting to pass a json string to a jsx file so that I could parse it and do something with it in the script.

I evaluate json2.js like so:

const json2File = `${root}/js/json2.js`;
csiRun.evalScript(`$.evalFile('${json2File}')`);

I evaluate a script like so:

$('#create-html').click(function() {

csiRun.evalScript(`setupArtTemplate()`, jsxResult => {
csiRun.evalScript(`main('${jsxResult}')`);
});
})

In my script I then try to parse the data like so:

function main(layoutDetails) {
try {
var detailsParsed = JSON.parse(layoutDetails);
} catch (error) {
alert(layoutDetails);
alert('Cannot parse data, error: ' + error)
}

}

The error I receive is 

Cannot parse data, error: TypeError: undefined is not an object

However as you can see I alert layoutDetails which does show the object as a json string.  But it doesn't parse.  Any idea what I'm doing wrong?