Uncaught (in promise) ReferrenceError: Cannot access 'formData' before initialization at HTMLFormElement.<anonymouse> (solution)

I was working with a javascript form submission. but I got this error which is like below:

I was trying to solve and search this type of error why happen.
finally, I find out the point why this is happening: this is happening because I write the variable name and the instance name are the same spelling: which is like below screenshot :

and after that, I do the correction in instance name spelling which is like below screen-shot:

and now it's working nicely there is no error/warning. please see below:
this is my browser console screen-shot:

see there is no warning.
and again see the network tabs screen-shot of my browser:

this is a show a success message.
.
that's it.
.
Happy Coding.
osman forhad
Mobile & Web Application Developer💻