/**
 * 将 URL 查询字符串转换为对象。重复参数保留为数组，单值参数保留为字符串。
 * @function urlParamToObj
 * @memberof module:url
 * @param {string} url 要解析的 URL 字符串
 * @returns {Record<string, string | string[]>} 查询参数对象
 * @throws {TypeError} url 不是字符串时抛出
 */

function urlParamToObj(url) {
  if (typeof url !== 'string') {
    throw new TypeError('url must be a string')
  }

  const queryStart = url.indexOf('?')
  if (queryStart === -1) return {}
  const hashStart = url.indexOf('#', queryStart)
  const query = url.slice(queryStart, hashStart === -1 ? undefined : hashStart)
  const sp = new URLSearchParams(query)
  const obj = {}
  for (const [key, value] of sp.entries()) {
    if (Object.prototype.hasOwnProperty.call(obj, key)) {
      obj[key] = Array.isArray(obj[key]) ? [...obj[key], value] : [obj[key], value]
    } else {
      obj[key] = value
    }
  }
  return obj
}

export default urlParamToObj