flow-upgrade

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

Install using yarn add flow-upgrade. We expect prettier to be installed as a peer dependency wherever you are running flow-upgrade.

You can then run:

yarn run flow-upgrade <current flow version> <target flow version>

You may also use npx:

npx flow-upgrade <current flow version> <target flow version>

We also supply the flow-codemod binary:

yarn run flow-codemod <codemod name>

If you just want to run a codemod without specifying Flow versions.

Options

all

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

prettierrc

Path to a .prettierrc file to use. Upgrade codemods rely upon prettier to print the resulting code after transformation. If this is not provided, we will just use the defaults.