class UrlBuilder {
  constructor(url) {
    this.orginurl = url;
    this.baseurl = url;
    this.checked = false;
  }

  addKV(key, value) {
    if (typeof (value) == 'undefined') {
      return this;
    }
    this._checkurl();
    let str = encodeURIComponent(key) + '=' + encodeURIComponent(value);
    this.baseurl += str;
    return this;
  }

  clear() {
    this.baseurl = this.orginurl;
    this.checked = false;
  }

  _checkurl() {
    if (!this.checked) {
      if (this.baseurl.indexOf('?') === -1) {
        this.baseurl += '?';
      } else {
        this.baseurl += '&';
      }
      this.checked = true;
    } else {
      this.baseurl += '&';
    }

  }
}

module.exports = UrlBuilder;