Validata is a Clojure library to validates maps. Its goals are:

provide a simple, idiomatic Clojure API
avoid using macros for the API
validate data, not transform or coerce it
make validation functions easy to compose
make validation functions easy to extend
use simple, easy-to-understand internals

There are many alternatives for validation in Clojure; I list some alternatives below. My goal is to make validata clean and simple relative to some of the other options.

Usage

Add this to your project.clj dependencies:

[validata "0.1.8"]

Here is an example:

(ns example.core
  (:require [validata.core :as v]))
(def validations
  {:uuid        [v/uuid-string v/required]
   :name        [v/string v/required]
   :notes       [v/string]
   :created-at  [v/timestamp-string]
   :updated-at  [v/timestamp-string]})
(v/errors {} validations)
; {:uuid ["key is required"], :name ["key is required"]}
(v/errors {:uuid "e0da523c-fdfc-46d5-bf6d-a895dd3235c1"} validations)
; {:name ["key is required"]}
(v/errors {:uuid "e0da523c-fdfc-46d5-bf6d-a895dd3235c1"
           :name "validata"
           :notes 2.7128} validations)
; {:notes ["value must be a string"]}
(v/errors {:uuid "e0da523c-fdfc-46d5-bf6d-a895dd3235c1"
           :name "validata"} validations)
; {}
(v/valid? {:uuid "e0da523c-fdfc-46d5-bf6d-a895dd3235c1"} validations)
; false
(v/valid? {:uuid "e0da523c-fdfc-46d5-bf6d-a895dd3235c1"
           :name "validata"} validations)
; true

To display errors for extra (unexpected keys), use this form of errors:

(v/errors {:uuid "ed2b4b7d-1111-47e1-aa79-5b204758cd01"
           :name "validata"
           :junk 42} validations false)
; {:junk [:error "key is unexpected"]}

Limitations

only validates top-level keys and values
strings are not internationalized

Other Validation Libraries

Clojure has many validation libraries; here are a few I've looked at:

The libraries have varying goals and approaches; take a look and give them a try. Please let me know if you see ideas that would benefit this project.

License

Distributed under the Eclipse Public License, the same as Clojure.