decide.nolog.cz/app/validators/valid-collection.js

import BaseValidator from 'ember-cp-validations/validators/base';

export default BaseValidator.extend({
  validate(value, options) {
    if (options.active === false) {
      return true;
    }

    var valid = value.every((element) => {
      return element.get('validations.isValid');
    });

    if (valid) {
      return true;
    } else {
      return 'all elements must be valid';
    }
  }
});