Errors and linting

Type checking is done by Flow. To permit Flow to type check your files in the project, you must add the // @flow comment (see how it works: Flow - Docs). To see what is the error, go with the cursor to the editor gutter, near the white dot. It will appear a red box with the error, like that:

Errors will be shown also at the bottom of the editor:

To be able to apply the Flow type checking also in a file that is not an element of a project, you could activate the option in Tools > JavaScript Enhancements > Flow > Use Flow checker on current view (Not used in project):

You can navigate errors in a project using:

Shortcut	Description
ctrl + alt + c	Go to next JavaScript error
ctrl + alt + v	Go to previous JavaScript error

or opening the Sublime Text Command Palette and typing Flow: :