app/code/Macademy/JsFun/view/frontend/requirejs-config.js

/*
The "*" after map makes this alias available to all JavaScript components.

The format for aliases is: "alias": "Namespace_Module/js/filename"

"Namespace_Module/js/filename"
>> maps to >>
Namespace/Module/view/[area]/web/js/filename.js

Paths can be used for non-AMD JavaScript modules & external files, but be sure
to not include the ".js" extension in any of these usages.
*/
var config = {
    "map": {
        "*": {
            "fadeInElement": "Macademy_JsFun/js/fade-in-element"
        }
    },
    "paths": {
        "vue": "https://cdn.jsdelivr.net/npm/vue/dist/vue"
    }
}

app/code/Macademy/JsFun/view/frontend/templates/block-promo-effects.phtml

<script>
// After defining an alias, it can then be used when requiring dependencies.
require([
    'jquery',
    'fadeInElement'
], function(
    $,
    fadeInElement
  ) {
    'use strict';

    $(function() {
        fadeInElement('.block-promo');
    });
});
</script>