This layer setups Emacs for working with flow files. It provides syntax checking
  throught flycheck-flow, and autocompletion throught company-flow. You also
  can use check types and jump to definition of symbols using flow-minor-mode.
It has some problems, like not working properly with the javascript layer.
Run git clone https://github.com/stevenremot/spacemacs-layer-flow.git ~/.emacs.d/private/flow/.
  Then declare the flow layer in your .spacemacs.
| Key Binding | Description | 
|---|---|
| M-. | Jump to definition | 
| C-c C-c t | Check the type of a symbol | 
| C-c C-c s | Display all flow errors in the project |