A function for processing user input to use as an argument.
A void return value will use the default value for the argument or start a prompt.
Any other truthy return value will be used as the evaluated argument.
If returning a Promise, the resolved value will go through the above steps.
A function for processing user input to use as an argument. A void return value will use the default value for the argument or start a prompt. Any other truthy return value will be used as the evaluated argument. If returning a Promise, the resolved value will go through the above steps.