Fineswap

This plugin will make developers and site builders (hopefully very) happy.
It enables site administrators to supply additional styles or/and scripts to 
be loaded alongside the theme’s resources. It will work regardless which 
theme the site is running, which makes it brilliant for adding custom 
programming and content blocks.
Styles and scripts can be either entered manually or loaded from 
external URL’s.
Brought to you by <a href="http://fineswap.com/?utm_source=wordpress&utm_medium=plugin&utm_term=readme-desc&utm_campaign=custom-resources" title="A blog and a mobile app advocating sustainability and green living" rel="nofollow ugc">Fineswap</a> Team.

Custom Resources

Easily load additional styles and scripts (for both front and backend pages). Works by direct inline embedding or by using URL's.

Palasthotel GmbH

greatestview

In some critical cases you cannot wait for a JavaScript file to load. Then you can benefit from better performance, if you embed the JavaScript code directly into the <code><script></code> tag. This is where this plugin comes in: It provides a filter <code>embed_javascript_file_content_handles</code>, which takes JavaScript handles and echos their code content into the DOM instead of linking to a file.
Please beware that placing lots of embedded JavaScript code can be critical! First you lose caching benefits and second the document size can increase easily. A general rule of thumb is that you should only consider JavaScript files for inline placement, which are critical and which have a file size lower than ~500 Bytes.
<h4>Example</h4>
<pre><code>add_action( 'wp_enqueue_scripts', 'my_scripts' );
function my_scripts() {
 // Some critical script is enqueued
 wp_enqueue_script( 'js-detection', get_template_directory_uri() . '/js/js-detection.js' );
}

/**
 * Define JavaScript handles to be echoed inline in the html head section.
 */
add_filter( 'embed_javascript_file_content_handles', 'my_embed_javascript_file_content_handles' );
function my_embed_javascript_file_content_handles( $handles ) {
 $scripts = [ 'js-detection' ];

 return array_merge( $handles, $scripts );
}
</code></pre>

Embed JavaScript File Content

Boosts performance of critical short JavaScript files by allowing to embed their code instead of linking to files. Script positions and extra scripts  …

Custom Resources vs Embed JavaScript File Content