When someone asks you to add a configuration option to an API, see if you can solve their problem (and many more) using the principles of Inversion of Control and Composition.

Links:
- https://github.com/paypal/downshift/issues/537
- https://github.com/paypal/downshift/blob/v2.0.20/src/downshift.js
- https://github.com/paypal/downshift/blob/v2.0.20/src/utils.js
- https://github.com/paypal/downshift/issues/319
- https://github.com/paypal/downshift/pull/320
- https://en.wikipedia.org/wiki/Inversion_of_control
- https://en.wikipedia.org/wiki/Function_composition_(computer_science)