Do you want to request a feature or report a bug?
feature

What is the current behavior?

• Jest (or any other testing framework for that matter) doesn't have a way of generating incremental code coverage.
• It would be very beneficial when I am trying to cover those last few conditionals to be able to immediately see the updated coverage (either html or text) immediately without having to stop and re-run jest with --coverage

What is the expected behavior?

• Incremental coverage updates, updating coverage info of the files that I am currently writing testcases for.

Please provide your exact Jest configuration and mention your Jest, node,
yarn/npm version and operating system.

• Node: 8.9.4
• Ubuntu 17.10
• Yarn: 1.3.2
• Jest: 22.1.1