concat

Combines two Results such that if they're both successful (Ok) their values are concatenated. Otherwise returns the failure.

Signature

Type(what is this?)

forall a, b: (Result a b).(Result a b) => Result a b
where b is Semigroup

Documentation

Combines two Results such that if they're both successful (Ok) their values are concatenated. Otherwise returns the failure.

Note that values are expected to be Fantasy Land 1.x semigroups and implement a concat method.

Example:

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

Result.Ok([1]).concat(Result.Ok([2]));
// ==> Result.Ok([1, 2])

Result.Ok([1]).concat(Result.Error([2]));
// ==> Result.Error([2])

Result.Error([1]).concat(Result.Error([2]));
// ==> Result.Error([1])

Result.Error([1]).concat(Result.Ok([2]));
// ==> Result.Error([1])

Properties

Source Code

Defined in source/result/result.js at line 75, column 19

{
    /*~*/
    Error: function concat(aResult) {
      assertResult('Result.Error#concat', aResult);
      return this;
    },

    /*~*/
    Ok: function concat(aResult) {
      assertResult('Result.Ok#concat', aResult);
      return aResult.map(xs => this.value.concat(xs));
    }
  }