how to send data from javascript to python flask

1/* You can create a node.js web server and use Fetch/AJAX POST requests to send 
2data. 
3*/
4/* Python Route Code */
5@app.route('/postmethod', methods = ['POST'])
6def get_post_javascript_data():
7    jsdata = request.form['javascript_data']
8    return json.loads(jsdata)[0]
9/* Javascript Send Data */
10fetch('Yourdomain.com/postmethod', {
11  method: 'POST',
12  headers: { 'Content-Type': 'application/json' },
13  body: JSON.stringify({
14  	'foo': 'bar'
15  }),
16})
17  .then((res) => res.json())
18  .then((data) => {
19    // Do some stuff ...
20  })