External JavaScript file is not getting added when running on Flask

Step 1: Create folder with name static on project root

Step 2: Add static files in static folder

Step 3 Add in template

<script type="text/javascript" src="{{ url_for('static', filename = 'hello.js') }}"></script>

Serve the map.js file as a static resource:

• move the file to a static/ subdirectory of your package

• generate a static URL for it in a Jinja2 template like so:

   <script type="text/javascript"
           src="{{ url_for('static', filename='map.js') }}"></script>
  

The filename parameter takes a relative path; you can use subdirectories was needed.