mapFailure

Transforms the failure value inside a Validation structure with an unary function without changing the status of the validation. That is, Success values continue to be Success values, Failure values continue to be Failure values.

Signature

Type(what is this?)

forall a, b, c:
  (Validation a b).((a) => c) Validation c b

Documentation

Example:

const { Success, Failure } = require('folktale/validation');

const upcase = (a) => a.toUpperCase();

Success('a').mapFailure(upcase);
// ==> Success('a')

Failure('a').mapFailure(upcase);
// ==> Failure('A')

Properties

Source Code

Defined in source/validation/validation.js at line 70, column 23

{
    /*~*/
    Failure: function mapFailure(transformation) {
      assertFunction('Validation.Failure#mapFailure', transformation);
      return Failure(transformation(this.value));
    },

    /*~*/
    Success: function mapFailure(transformation) {
      assertFunction('Validation.Failure#mapFailure', transformation);
      return this;
    }
  }