Want to add a custom.js file for a child-theme in a swift way? Use following code in your theme’s functions.php file OR in site specific plugin.
get_stylesheet_directory_uri() . '/YOUR_SCRIPT_FILE.js',
Notes: You don’t have to use the version number 4.7.3, but you do need to write some plausible version number (like of your WordPress core version) or the keyword null instead.
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