Egkyron

Egkyron is a validation infrastructure library, with the goal of being capable to adapt to various kinds of Javascript model objects, e.g. plain JSON, Knockout etc and environments, e.g. Node, Browser+AngularJS, Browser+React etc. The word egkyron means valid in Greek.

Egkyron undertakes the task of model validation in addition to form validation. Form validation has already been implemented for the targeted frameworks, such as AngularJS. This means that, given some data (the model) and a defined set of validation rules, it decides the validity of the overall model and individual parts of it. It provides infrastructure for error message generation of the invalid parts of the model. And it provides infrastructure for integrating with form validation, so that error messages can be displayed to the user as appropriate.

Egkyron tries to provide the infrastructure for validation up to the generation of a data structure containing detailed information about the errors of the model. It is up to the user how will these error be displayed. Look in the src/examples folder for sample implementations of the display logic.

Here is a plunk version of the Angular example.

Changes

• (2017/08/10) Typings for using egkyron with Typescript
• (2017/08/10) Incorporated the condition branch into master; it adds the condition constraint parameter to conditionally deactivate the validation
• (2016/06/09) The React example is in the master.

Implementation state

Currently the core has been implemented, as well as Node and AngularJS integration. An example in React is also added, using the NPM package directly. Integration with React for this example is so simple, that no separate packaging project was made.

Use cases - what was it made for

1. A single, large model, displayed in many views
2. The need to separate business logic, in this case the validation rules, from the view
3. No form validation (e.g. server-side)

Anti-use cases

1. Simple forms

Design

The concerns in a validation solution addressed by Egkyron are:

1. The core validation logic
2. Model introspection strategies
3. Adapting to different environments (e.g. Node, Browser)
4. Common validators

Moreover Egkyron takes care of:

1. Packaging its components for the supported environments

Example usage

// SETUP
//   all the following objects need to be created once and can then be reused
// the validatorRegistry knows the various validators
var validatorRegistry = makeValidatorRegistry();
// the introspector knows how to extract information from the model
var introspector = new ConstructorIntrospector();
// the validator implements the core logic
var validator = new Validator(validatorRegistry, introspector);

// VALIDATE
// the data to validate
var data = ...
// validate and get the results
var results = validator.validate(data);

// USE THE RESULTS
// the overall validity flag
var isValid = results._thisValid && results._childrenValid !== false;
// the error message for the `required` validator of the `data.name` field
var nameErrorMsg = results._children['name']._validity['required'].message;

Building

npm install
bower install
gulp

To clean, simply do:

rm -rf target

Installing to npm

The directory that will get installed is target/dist/node; it contains all the things needed. So, after building, do:

cd target/dist/node
npm publish

Alternatively, you may want to link for development purposes:

cd target/dist/node
npm link