how to add a custom javascript file to our theme

Question

I add custom css files to my theme, but when I try to do the same for the javascript files, they dont seem to work, this means that the javascript on the html files is working properlly, but if I transfer it to the custom javascript file it doesnt. Am I adding the custom javascript file correctly to wordpress?

if (! function_exists('custom_jsfiles')) {
    add_action('wp_enqueue_scripts', 'custom_jsfiles');
    function custom_jsfiles() {wp_enqueue_script('custom_js', home_url().'/wp-content/themes/mytheme/custom-js.js');}
}

Answer 1

Having this issue for months and I got it now running when I posted the question here. the issue is that the wp_enqueue_script needs to have the script file register first. So I have it working this way!

if (! function_exists('custom_jsfiles')) {
   add_action('wp_enqueue_scripts', 'custom_jsfiles');
      function custom_jsfiles() {
      wp_register_script('custom_js', get_theme_file_uri().'/mytheme/custom-js.js');
      wp_enqueue_script('custom_js');
   }
}

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updating the answer, the path wasnt correct, also has jacob said, no need to register them And now its working

function ad_ficheiros(){
    wp_enqueue_script('custom_js', get_template_directory_uri().'/inc/custom-js.js', array(), '1.15', true);
}
add_action('wp_enqueue_scripts', 'ad_ficheiros');

here the file is on a folder called inc inside the themes folder, also added two more parameters, the file version and if it is to be shown in the header or footer(false or true).