/**
 * Converts any value to string.
 *
 * @param {*} value
 * @returns {String}
 */
export function stringify(value) {
  let result;

  switch (typeof value) {
    case 'string':
    case 'number':
      result = `${value}`;
      break;

    case 'object':
      result = value === null ? '' : value.toString();
      break;
    case 'undefined':
      result = '';
      break;
    default:
      result = value.toString();
      break;
  }

  return result;
}

/**
 * Checks if given variable is defined.
 *
 * @param {*} variable Variable to check.
 * @returns {Boolean}
 */
export function isDefined(variable) {
  return typeof variable !== 'undefined';
}

/**
 * Checks if given variable is undefined.
 *
 * @param {*} variable Variable to check.
 * @returns {Boolean}
 */
export function isUndefined(variable) {
  return typeof variable === 'undefined';
}

/**
 * Check if given variable is null, empty string or undefined.
 *
 * @param {*} variable Variable to check.
 * @returns {Boolean}
 */
export function isEmpty(variable) {
  return variable === null || variable === '' || isUndefined(variable);
}

/**
 * Check if given variable is a regular expression.
 *
 * @param {*} variable Variable to check.
 * @returns {Boolean}
 */
export function isRegExp(variable) {
  return Object.prototype.toString.call(variable) === '[object RegExp]';
}