bootstrapvalidator/src/js/validator/choice.js

The best jQuery plugin to validate form fields. Designed to use with Bootstrap 3

(function($) {
    $.fn.bootstrapValidator.i18n.choice = $.extend($.fn.bootstrapValidator.i18n.choice || {}, {
        'default': 'Please enter a valid value',
        less: 'Please choose %s options at minimum',
        more: 'Please choose %s options at maximum',
        between: 'Please choose %s - %s options'
    });

    $.fn.bootstrapValidator.validators.choice = {
        html5Attributes: {
            message: 'message',
            min: 'min',
            max: 'max'
        },

        /**
         * Check if the number of checked boxes are less or more than a given number
         *
         * @param {BootstrapValidator} validator The validator plugin instance
         * @param {jQuery} $field Field element
         * @param {Object} options Consists of following keys:
         * - min
         * - max
         *
         * At least one of two keys is required
         * The min, max keys define the number which the field value compares to. min, max can be
         *      - A number
         *      - Name of field which its value defines the number
         *      - Name of callback function that returns the number
         *      - A callback function that returns the number
         *
         * - message: The invalid message
         * @returns {Object}
         */
        validate: function(validator, $field, options) {
            var numChoices = $field.is('select')
                            ? validator.getFieldElements($field.attr('data-bv-field')).find('option').filter(':selected').length
                            : validator.getFieldElements($field.attr('data-bv-field')).filter(':checked').length,
                min        = options.min ? ($.isNumeric(options.min) ? options.min : validator.getDynamicOption($field, options.min)) : null,
                max        = options.max ? ($.isNumeric(options.max) ? options.max : validator.getDynamicOption($field, options.max)) : null,
                isValid    = true,
                message    = options.message || $.fn.bootstrapValidator.i18n.choice['default'];

            if ((min && numChoices < parseInt(min, 10)) || (max && numChoices > parseInt(max, 10))) {
                isValid = false;
            }

            switch (true) {
                case (!!min && !!max):
                    message = $.fn.bootstrapValidator.helpers.format(options.message || $.fn.bootstrapValidator.i18n.choice.between, [parseInt(min, 10), parseInt(max, 10)]);
                    break;

                case (!!min):
                    message = $.fn.bootstrapValidator.helpers.format(options.message || $.fn.bootstrapValidator.i18n.choice.less, parseInt(min, 10));
                    break;

                case (!!max):
                    message = $.fn.bootstrapValidator.helpers.format(options.message || $.fn.bootstrapValidator.i18n.choice.more, parseInt(max, 10));
                    break;

                default:
                    break;
            }

            return { valid: isValid, message: message };
        }
    };
}(window.jQuery));