flatiron/prompt — pull request #76 by badsyntax (2013-11-18 20:39:50+00:00)
Title: Modify users input before the running the validation.

As the title says, it would be a lot more useful if the before() callback was called on the users' input prior to validation.

I want to be able to do something like:

```javascript
{
name: 'date',
type: 'string',
required: true,
format: 'date-time',
default: 'now',
before: function(value) {
return value === 'now' ? new Date().toISOString() : value;
}
}
```

...but I cannot do that as the validation for the 'date-time' format will fail as it will be using the 'default' value ('now') instead of the transformed date value (new Date().toISOString()).

I've added a new test to check if the before callback is run prior to validation.