Bootstrap 4.0.0-beta modal won't work. Popper.js is breaking-Twitter bootstrap

I am creating a button to open up a modal when clicked.

<--Modal trigger-->
    <button type="button" data-toggle="modal" data-target="#myModal">Create a new category</button>

<--Modal body-->
<div id="myModal" class="modal fade" role="dialog">
    <div class="modal-dialog">

        <!-- Modal content-->
        <div class="modal-content">
            <div class="modal-header">
                <button type="button" class="close" data-dismiss="modal">&times;</button>
                <h4 class="modal-title">Modal Header</h4>
            </div>
            <div class="modal-body">
                <p>Some text in the modal.</p>
            </div>
            <div class="modal-footer">
                <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
            </div>
        </div>

    </div>
</div>

Somehow the trigger is not working. When button clicked the modal wont popup. My cdn are as follows:

<--Bootstrap css-->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css"
      integrity="sha384-/Y6pD6FV/Vv2HJnA6t+vslU6fwYXjCFtcEpHbNJ0lyAFsXTsjBbfaDjzALeQsN6M" crossorigin="anonymous">

<--Bootstrap and JQuery js-->
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.4/angular.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.0.0-beta/js/bootstrap.js"></script>

I am getting a popper.js error. I have had been getting this error on my other project. But installing and adding the popper.js to dev-dependencies and running ‘npm run dev’ had solved it the last time. This time somehow it won’t work.

My dev-dependencies in package.json:

"devDependencies": {
"axios": "^0.16.2",
"bootstrap-sass": "^3.3.7",
"cross-env": "^5.0.1",
"jquery": "^3.1.1",
"laravel-mix": "^1.0",
"lodash": "^4.17.4",
"vue": "^2.1.10",
"popper.js": "^1.12.5"

},

NOTE: I am using Laravel framework and have installed popper through Node.

HELP!