mapError

Transforms the value inside an Error without changing the context of the computation.

This feature is experimental!

This API is still experimental, so it may change or be removed in future versions. You should not rely on it for production applications.

Signature

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

Documentation

Transforms the value inside an Error without changing the context of the computation.

This is similar to .map, except it operates on Errors instead of Oks.

Example:

const Result = require('folktale/result');

Result.Error(1).mapError(x => x + 1);
// ==> Result.Error(2)

Result.Ok(1).mapError(x => x + 1);
// ==> Result.Ok(1)

Properties

Source Code

Defined in source/result/result.js at line 75, column 19
{
    /*~*/
    Error: function mapError(f) {
      assertFunction('Result.Error#mapError', f);
      return Error(f(this.value));
    },

    /*~*/
    Ok: function mapError(f) {
      assertFunction('Result.Ok#mapError', f);
      return this;
    }
  }
Stability
experimental
Licence
MIT
Module
folktale/result/result
Authors
Copyright
(c) 2013-2017 Quildreen Motta, and CONTRIBUTORS
Authors
  • Quildreen Motta
Maintainers
  • Quildreen Motta <queen@robotlolita.me> (http://robotlolita.me/)