Can't load popper.js with webpack and Laravel mix

I'm using bootstrap 4 beta and Laravel 5.4 on my project and loading my js dependencies with npm and laravel mix. So far everything has been working great, except when i'm trying to use the booostrap js methods. It throws me the error "Bootstrap dropdown require Popper.js", so i downloaded and loaded it in the bootstrap.js and webpack.mix.js files, but it still is asking for this dependency, can you tell me what i did wrong ?

boostrap.js

try {
  window.$ = window.jQuery = require('jquery');

  require('popper.js');
  require('datatables.net');
  require('datatables.net-autofill');
  require('datatables.net-buttons');
  require('bootstrap');
} catch (e) {
  console.log(e);
}

webpack.mix.js

const { mix } = require('laravel-mix');

mix.js([
  'resources/assets/js/app.js',
  'node_modules/jquery/dist/jquery.min.js',
  'node_modules/http://ift.tt/2gB6uat',
  'node_modules/bootstrap/dist/js/bootstrap.js',
  'node_modules/http://ift.tt/2nqzFfD',
  'node_modules/datatables.net-buttons/js/dataTables.buttons.js',
  'node_modules/datatables.net-autofill/js/dataTables.autoFill.js',
], 'public/js')
  .sass('resources/assets/sass/app.scss', 'public/css');

via Chebli Mohamed