Using Google Analytics in an enqueued JS file

I have a JS file custom-head.js that I have enqueued to run in the header as noted in functions.php here:

function enqueue_files() {      wp_enqueue_script( 'head_scripts', get_stylesheet_directory_uri() . '/js/custom-head.js', array('jquery'), null, false); } add_action( 'wp_enqueue_scripts', 'enqueue_files' ); 

Within that file I want to include my Google Analytics code. Yes, I realize I can add it to header.php or functions.php, but ideally I want to keep all of my scripts that are designed to be in the header in this one custom-head.js file.

//Global site tag (gtag.js) - Google Analytics jQuery(document).ready(function($  ) {     async src=""  //check if on the live domain versus dev if (document.location.hostname == '') {   window.dataLayer = window.dataLayer || [];   function gtag(){dataLayer.push(arguments);}   gtag('js', new Date());    gtag('config', 'G-xxxxx'); }  }); 

However, I am not getting the tag to fire correctly. Can you please advise on how to add these scripts?