I have a Drupal 8 site up and running with modules that were manually installed. I want to generate an appropriate composer.json file to manage these using Composer.
The closest I could find to achieve this is an old Drupal 7 module, Composer Generate, mentioned in how to install package via composer? but that only works with Drupal 7 and it isn't any longer developed.
How to move Composer created folder of drupal-8.x.x up one level to html? suggests that third-party modules can/should be handled with Composer, but I would like to not have to manually rewrite the composer.json file to achieve this.
Is there a Drupal 8 / Composer / Drush way to accomplish this, or is manually updating the composer.json the only option?