A utility for upgrading your codebase to the latest version of Flow.

To run this utility to upgrade your codebase you can use yarn create:

yarn create flow-upgrade

This is a shorter version which is equivalent to:

yarn global add flow-upgrade
flow-upgrade

You may also use npx:

npx flow-upgrade

By default, Flow will only upgrade files that have an // @flow header comment. If you want to upgrade all of your JavaScript files you may pass in the --all:

yarn create flow-upgrade --all