Turns a WordPress JavaScript file into a module while still supporting wp_add_inline_script()

make-script-module.php

<?php

// Below function will ensure that any scripts added using wp_add_inline_script() are not touched during the filtering process.
// We need to do this because the filte runs after the inline scripts have been concatenated: https://github.com/WordPress/WordPress/blob/6.1.1/wp-includes/class-wp-scripts.php#L406
function make_scripts_modules( $tag, $handle, $src ) {
    
            if ( 'your-script-handle' !== $handle ) {
                return $tag;
            }
    
            $id = $handle . '-js';
    
            $parts = explode( '</script>', $tag ); // Break up our string
    
            foreach ( $parts as $key => $part ) {
                if ( false !== strpos( $part, $src ) ) { // Make sure we're only altering the tag for our module script.
                    $parts[ $key ] = '<script type="module" src="' . esc_url( $src ) . '" id="' . esc_attr( $id ) . '">';
                }
            }
    
            $tags = implode( '</script>', $parts ); // Bring everything back together
    
            return $tags;
}
add_filter('script_loader_tag', 'make_scripts_modules' , 10, 3);