theme-independent CSS/JS files

Question

So far I did the following task to add theme-dependent CSS/JS files; I added to the theme's functions.php this code, then created the relevant CSS and JS files:

function my_theme_enqueue_styles() {
    wp_enqueue_style( 'parent-style', get_parent_theme_file_uri() . 'style.css' );
}
add_action( 'my_theme_enqueue_styles', 'wp_enqueue_styles' );

function my_theme_enqueue_assets() {
    wp_enqueue_script( 'behavior', get_theme_file_uri( 'behavior.js' ), array(), null, true );
}
add_action( 'wp_enqueue_scripts', 'my_theme_enqueue_assets' );

But what if I want my CSS and JS to be theme-independent? Say, I want to had a few lines of CSS and JS that will be available in all themes whatsoever.

Is there a way to do so in WordPress outside the WordPress User Interface?

Answer 1

Use the following code to create a simple plugin. Create a directory tia inside plugins directory and save the code in a file tia.php then put it inside tia directory and finally activate from plugin page.

<?php
/**
 * Plugin Name: Theme Independent Assets
 * Author: Obi
 * Version: 0.0.7
 */

if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

function tia_enqueue_scripts() {
    wp_enqueue_script( ... );
    wp_enqueue_style( ... );
}
add_action( 'wp_enqueue_scripts', 'tia_enqueue_scripts' );