Backbone Model Validation

validation.js

_.extend(Backbone.Model.prototype, Backbone.Events, {

    errors: [],

    validate: function (attrs) {

        //reset
        this.errors = [];
        var model = this;
        
        for (attr in attrs) {
            if (attrs.hasOwnProperty(attr)) {
                //get valiators from attribute
                var validators = _.select(this.validation, function(validator) {
                    return validator.attr == attr;
                }, model);

                _.each(validators, function(v) {

                    var validator = global.Validators[v.validator];
                    var result = validator.validate(attrs[attr], v);

                    if (!result) {
                        //only add one message for a property at a time
                        var existingAttrError = _.any(model.errors, function(e) {
                            return e.attr == v.attr;
                        }, model);

                        if (!existingAttrError) {
                            model.errors.push({ attr: v.attr, error: (v.message || v.attr + validator.message) });
                        }
                    }

                }, model);
            };

        }
        if (_.any(this.errors)) { return this.errors; };
    },

    hasErrors: function () {
        return _.any(this.errors);
    }

});


global.Validators = {

    required: {

        message: " can't be blank",
        validate: function (value, args) {
            return !_.isEmpty(value);
        }

    },

    minLength: {

        message: ' does not meet required length',
        validate: function (value, args) {
            return value.length > args.minLength;
        }

    },

    email: {
        message: ' must be an email address',
        validate: function (value, args) {
            var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
            return reg.test(value);
        }
    }
};

//usage
Model = Backbone.Model.extend({

  validation: [
    { attr: "Name", validator: "required" }
  ]

});

var model = new Model();
model.bind("error", function(model, errors) { });
model.save({Name:""});