Error Monad and Monad Transformer for Akh Javascript Monad Library

The ErrorT transformer, ErrorT, adds error control to a monad. The base type, Error, provides error logic on its own.

``bash


To use as standalone package

$ npm install --save akh.error

To use as part of akh library

$ npm install --save akh
`

Usage

The ErrorT and Error implement the [Fantasy Land][fl] monad, functor, and applicative functor interfaces.

`js
// Error monad
require('akh.error').Error
require('akh').Error

// Error monad transformer
require('akh.error').ErrorT
require('akh').ErrorT
`

#### Error.run(m, ok, err), m.run(ok, err)
Perform a error computation m and invoke ok if it succeeds and err if it fails.

`js
const c =
Error.of(3)
.map(x => -x);

Error.run(c, console.error, console.log); // logs: -3
`

#### ErrorT.run(t, ok, err), t.run(ok, err)
Same as Error.run but for a monad transformer. Returns an Error value inside of the inner monad.


#### Error.attempt(m, def), m.attempt(def)
Perform an error computation m and return the result if it succeeds and def if it fails.

#### Error.try(m, e), m.try(e)
Perform an error computation m and return the result if it succeeds and invoke e if it fails




Error Interface

#### Error.fail(x)
#### ErrorT(m).fail(x)
Construct a error value value.


#### Error.handle(f)
#### ErrorT(m).handle(f)
Handle an error.




Contributing

Contributions are welcome.

To get started:

`bash
$ cd akh-error
$ npm install # install dev packages
$ npm test # run tests
``

[fl]: https://github.com/fantasyland/fantasy-land