Use the ($this->document->addScript) to add scripts located in extension/

Trying to upgrade a module from 3.0 to 4.0. Now, since all extension files (include any scripts/css files) are located in the extension/ folder, im struggling to import them.

Earlier, I used:
$this->document->addScript('view/javascript/mymodule/modulescript.js');
as the files was located in admin/view/javascript/mymodule/modulescript.js

Now, the script is located in extension/mymodule/admin/javascript/modulescript.js

Anyone know how do it?
Sorry my bad coding skills

Try with

Unfortunately it didnt work. I got this working, but Im not sure if its right or wrong:

If that javascript file is not in view....then try