dropzone is not defined on my laravel project

my drop zone is not defined but i have already set it on bootstrap.js file, then i have declare for new dropzone method with the id i set with file, but i dont know why its always not define, please somebody help

// on folder assets/js/bootstrap.js

   window.Dropzone = require('dropzone');

   Dropzone.autoDiscover = false;

// on blade file

@section('scripts')

<script>
    var drop = new Dropzone('#file', {
        url: ""
    });
</script>

@endsection

via Chebli Mohamed