Jinja2 variable to Javascrip gives object of type Undefined

Background

After completing a form I redirect the user to the Post page, with the content he has input on that form. The description input, which is a textarea, has support for markdown text; that markdown text I want to parse before the page loads into html using showdown. After submitting the form I save the text in a Project object that I pass on the route to the html.

Route called when form is submitted

''' Route of dynamically generated post. '''
@bp.route('/projects/post/<post_id>')
def post(post_id):
   .....
   return render_template('post.html', title=f'Project {post_id}', project=project)

I want to be able to send the `project.background_input' from HTML to javascript to I can use

const bg_intro = document.getElementById('project-description-intro')
bg_intro.innerHTML = ` ${converter.makeHtml(project.background_intro)} `

I tried the following:

1. In my script before the bundle.js with the module that converts markdown into html

   <script type=text/javascript>
     dosth({{ project.background_intro|tojson|safe }}); // ERROR OBJECT OF TYPE UNDEFINED
   </script>
   <script src="{{ url_for('static', filename='assets/js/post-convert/bundle.js') }}"></script>
   

2. Create global js variable.

   Uncaught ReferenceError: background_intro is not defined

   <script type=text/javascript>var text = {{project.description_intro}};</script> 
   // Uncaught ReferenceError: description_intro is not defined
   <script src="{{ url_for('static', filename='assets/js/post-convert/bundle.js') }}"></script>
   

How should I pass my jinja2 variable to javascript?

EDIT:

I captured the output of my project.description_intro on my post route as following:

print(f'Type is {type(project.description_intro)} and the content: {project.description_intro}')

With the corresponding output:

Type is <class 'str'> and the content: This is a simple text, for testing purposes. This is **bold**. This is a list:
- l1
- l2

EDIT2:

bundle.js

function dosth(text1){
    console.log(text1); // 22:196 Uncaught ReferenceError: dosth is not defined
}

html file

<script type=text/javascript>
  dosth({{ project.description_intro|tojson|safe }}); 
</script>