How to add custom JS/CSS file, without modifying the template (from extension)?

Question

I am writing a custom extension, and i wanted to add specific JS and CSS into admin dashboard (on every page), and also different JS/CSS files on front-end...

I have seen many answers, but all of them talk about index.php modifications.. Is not there a simpler method, like worpdress has, something like this phseudo-code:

function AddMyScript(){
    echo '<link rel="stylesheet"..................
    //or $this->AddScript('myCss', 1.01, url......)
}
add_action('wp_head', 'AddMyScript');

also, please add two words about how to implement & call that default.php

Answer 1

Here is the documentation: https://docs.joomla.org/J3.x:Adding_JavaScript_and_CSS_to_the_page

If you wish to add different css and js to the front and back of the site then you should use a system plugin and test for which client it is like this:

class plgSystemRandomname extends JPlugin
{

   function onBeforeCompileHead()
   {
       $doc = JFactory::getDocument();
       $app = JFactory::getApplication();

       if ($app->isClient('site')){

         // add all yr scripts and stylesheets from the frontend, eg.
         $doc->addScript('/path/to/script.js');

       } elseif ($app->isClient('administrator')) {

         // add all yr js and css for the backend, eg.
         $doc->addScript('/path/to/different_script.js');

      }
   }

}

Here is the documentation for making a plugin: https://docs.joomla.org/J3.x:Creating_a_Plugin_for_Joomla

Note that isClient came in in J3.7 I think.