Data.Validation

The Validation(a, b) is a disjunction that's more appropriate for validating inputs, or any use case where you want to aggregate failures. Not only the Validation provides a better terminology for working with such cases (Failure and Success versus Left and Right), it also allows one to easily aggregate failures and successes as an Applicative Functor.

Example

varValidation=require('data.validation')varSuccess=Validation.SuccessvarFailure=Validation.Failure// Functions that need to do validation return one of two cases://// - A Success with the value they want to propagate.// - Some value representing one or more failures, using a semigroup.// Lists are the more straight-forward semigroup, so we just use them// here.functionisPasswordLongEnough(a){returna.length>6? Success(a)
: /* otherwise */Failure(["Password must have more than 6 characters"])}functionisPasswordStrongEnough(a){return/[\W]/.test(a)? Success(a)
: /* otherwise */Failure(["Password must contain special characters"])}// To aggregate the failures, we start with a Success case containing// a curried function of arity N (where N is the number of validations),// and we just use an `.ap`-ply chain to get either the value our Success// function ultimately returns, or the aggregated failures.functionisPasswordValid(a){returnSuccess(function(x){returnfunction(y){returna}}).ap(isPasswordLongEnough(a)).ap(isPasswordStrongEnough(a))}isPasswordValid("foo")// => Validation.Failure([// "Password must have more than 6 characters.",// "Password must contain special characters."// ])isPasswordValid("rosesarered")// => Validation.Failure([// "Password must contain special characters."// ])isPasswordValid("rosesarered$andstuff")// => Validation.Success("rosesarered$andstuff")

Installing

The easiest way is to grab it from NPM. If you're running in a Browser environment, you can use Browserify

$ npm install data.validation

Using with CommonJS

If you're not using NPM, Download the latest release, and require the data.validation.umd.js file:

varValidation=require('data.validation')

Using with AMD

Download the latest release, and require the data.validation.umd.js file:

require(['data.validation'],function(Validation){( ... )})

Using without modules

Download the latest release, and load the data.validation.umd.js file. The properties are exposed in the global folktale.data.validation object:

<scriptsrc="/path/to/data.validation.umd.js"></script>

Compiling from source

If you want to compile this library from the source, you'll need Git, Make, Node.js, and run the following commands:

$ git clone git://github.com/folktale/data.validation.git
$ cd data.validation
$ npm install
$ make bundle

This will generate the dist/data.validation.umd.js file, which you can load in any JavaScript environment.

Documentation

You can read the documentation online or build it yourself:

$ git clone git://github.com/folktale/data.validation.git
$ cd data.validation
$ npm install
$ make documentation

Then open the file docs/index.html in your browser.

Platform support

This library assumes an ES5 environment, but can be easily supported in ES3 platforms by the use of shims. Just include es5-shim :)

Licence

Copyright (c) 2013 Quildreen Motta.

Released under the MIT licence.