node-restify-validation/lib/error.js

```diff -Maintener wanted ``` Validation for REST Services built with [node-restify](https://github.com/mcavage/node-restify) in node.js

/*
 * The MIT License
 *
 * Copyright 2014 Timo Behrmann, Guillaume Chauvet.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

var _ = require('lodash');

function parseErrorMessage(errors, template) {
    var compiled = _.template(template || '<%= field %> (<%= type %>): <%= reason %>' );
    var key;
    var message = [];

    for (key in errors) {
        if (errors.hasOwnProperty(key)) {
            message.push(compiled({
                field: errors[key].field,
                type: errors[key].type,
                reason: errors[key].reason
            }));
        }
    }

    return message.join(', ');
}

module.exports.handle = function (errors, req, res, options, next) {
    if (options.handleError) {
        return options.handleError(res, errors, next);
    } else if (options.errorHandler) {
        res.send(new options.errorHandler(parseErrorMessage(errors, options.template)));
        return next(false);
    } else {
        res.send (409, {
            code: 'InvalidArgument',
            message: 'Validation failed',
            errors: errors
        });
        return next(false);
    }
};