inject jquery underscore backbone into page window

scriptify.js

/*
Version 0.0.1, 2018
Copyright (C) 2018 Jamal Boulhous (]d).

Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.

Ok, the purpose of this license is simple
and you just

DO WHAT THE FUCK YOU WANT TO.
*/

function ify (simbol = "$", name = "jQuery", url = "ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js", dokument = document, win = window) {
  var scripts = dokument.getElementsByTagName("script");
  var script = null;
  var filename = new RegExp(`^${name}.*\.js$`, "i");
  
  var found = false;
  for (var i = 0; i < scripts.length; i++) {
    script = scripts[i];
    // is this realy cool.
    if (filename.test(script.src)) {
      found = true;
      break;
    }
  }

  if (!found) {
    try {
      found = win[simbol] && win[name] && (win[simbol] === win[name]);
    } catch (err) {
      console.log(`ify error : ${err}`);
    }
  }

  if (!found) {
    // inject ;-)
    script = dokument.createElement("script");
    script.type = "text/javascript";
    
    var protocol = /^https:/i.test(dokument.location) ? "https" : "http";
    script.src = `${protocol}://${url}`;
    dokument.getElementsByTagName("body")[0].appendChild(script);
  }
  return found;
}

function scriptify(simbol = "$", name = "jQuery", url = "cdnjs.cloudflare.com/ajax/libs/jquery/1.12.4/jquery.js", dokument = document, win = window) {
  var found = ify(simbol, name, url, dokument, win);
  console.log(found, `${simbol} ${name} ${url}`)
}

function known_libs(name) {
  if (!KNOWN_LIBS[name]) return console.log('lib not found');
  scriptify.apply(null, KNOWN_LIBS[name]);
}

KNOWN_LIBS = {
  "jquery" : [],
  "underscore" : ["_", "underscore", "cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore.js"],
  "backbone" : ["Backbone", "Backbone", "cdnjs.cloudflare.com/ajax/libs/backbone.js/1.3.3/backbone.js"],
  "backbone_localsotrage": ["backbone_localstorage", "backbone_localstorage", "cdnjs.cloudflare.com/ajax/libs/backbone-localstorage.js/1.1.16/backbone.localStorage-min.js"],
};

async function do_after (seconds, fn, arg) {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      fn(arg);
      resolve();
    }, seconds * 1000);
    
  });
}

await do_after(0, known_libs, "jquery");
await do_after(2, known_libs, "underscore");
await do_after(4, known_libs, "backbone");
await do_after(6, known_libs, "backbone_localstorage");