type string: alpha and optional option combinations

[sajcics]

WHAT?
When I define alpha parameter in the optional field, the validator throws error.

EXAMPLE:
Here is an example how I defined rule for name field.
name: { type: 'string', optional: true, alpha: true, trimLeft: true },

the validator throws error field must be an alphabetic string. If I remove alpha then validation on empty field works.

EXPECTING:
When optional is set then alpha will not validate on empty string.

VERSION:
latest: 1.11.1
nodejs: 14

[erfanium]

It's expected, empty string is not a valid alpha pattern

[sajcics]

yes, but I have an optional set to true, which means that alpha should not be applied if string is empty.

[erfanium]

optional flag only cares about null and undefined values, it doesn't skip empty strings

[sajcics]

it will be great if empty string also consider as null and undefined for optional...because it's empty and do not representing anything

[erfanium]

You can add a preValidation middleware to delete these keys from object. it's more safe for the validator to be strict