required.js

import * as util from '../util';

/**
 *  Rule for validating required fields.
 *
 *  @param rule The validation rule.
 *  @param value The value of the field on the source object.
 *  @param source The source object being validated.
 *  @param errors An array of errors that this rule may add
 *  validation errors to.
 *  @param options The validation options.
 *  @param options.messages The validation messages.
 */
function required(rule, value, source, errors, options, type) {
  if (rule.required && (!source.hasOwnProperty(rule.field) || util.isEmptyValue(value, type || rule.type))) {
    errors.push(util.format(options.messages.required, rule.fullField));
  }
}

export default required;