formlyApiCheck

Internally

angular-formly depends on the library apiCheck to validate that you're using the functions and directives properly. If not, you will get errors and warnings if you do something wrong. Hopefully these errors and warnings are useful!

Custom apiCheck

You can use apiCheck to validate the api to your custom types. You can specify an apiCheck property on a type and a wrapper. For more information, see the formlyConfig documentation.