text: // @ts-check
  
  /**
   * Is valid password (minimum 4 characters, no spaces)
   * @param {string} value String to validate
   * @returns {'format' | 'length' | null} Error string or null if valid
   */
  export function isPassword (value) {
    if (value.length < 4) {
      return 'length';
    } else {
      return /^([A-Za-z0-9!@#$%^&*-+_=])+$/.test (value) ? null : 'format';
    }
  }
  