Generate assets using Laravel model data

I am trying to generate a unique JS file for each of a certain model in my app. I need a JS file specific to each "Campaign" entity. I am trying to do this with the following steps:

1. Compile and minify JS asset with template tags in place of variables to replace later
2. Use an http query to hit my application's API and retrieve the models, and
3. Use a templating language to replace the variables and in the minified template and save to many JS files

Here is my code right now:

elixir((mix) => {
// Fetch all campaigns
axios.get('http://ift.tt/2lOaNPV', (response) => {

   // For each campaign, read the template file
    _.forEach(response, (campaign) => {
        fs.readFile('resources/assets/js/tracking/templates/campaign-tracker.tmpl', 'utf8', (err, data) => {
            // Replace template tags with model data
            var compiled = _.template(data);
            var output = compiled({ga_code: campaign.property_id});

            // write output to public folder
            fs.writeFile('public/js/campaigns/' + campaign.id + ".js", output, 'utf8', () => {
                gutil.log('Completed '+campaign.name)
            })
        });
    })
})

mix.sass('app.scss')
   .webpack('app.js')
   .webpack('tracking/pixel.js');

});    

I've tried this a number of different ways... basically the issue seems to be that Elixir is not waiting for the asynchronous response from the API. Nothing inside the AJAX callback is being executed

I also wanted to get feedback on if there is a better template language to use than the basic _.template that already integrates with , or a better way to read and write the templates and files than fs.

My other thought for pulling this off would be to serve the JS from a route that dynamically generates it. So for instance campaigns/{campaign}/script.js would serve a blade template that resulted in JS being returned. But if I do that, how would I turn JS into a blade file? I would need to write JS and then somehow turn it into a blade template for rendering. I also am worried that this would be a much slower loading page than a straight up JS file.

I think this also has applications in css, for instance if each user could configure CSS settings for the app and you wanted to generate a stylesheet per user. Thank you!

via Jeff