Method isSupportWebp

src/openlayers/mapping/WebMap.js:5348–5376

* @private * @function WebMap.prototype.isSupportWebp * @description 判断是否支持webP * @param {*} url 服务地址 * @param {*} token 服务token * @param {*} proxy * @returns {boolean}

(url, token, proxy)

   * @returns {boolean}
   */
  isSupportWebp(url, token, proxy) {
    // 还需要判断浏览器
    let isIE = this.isIE();
    if (
      isIE ||
      (this.isFirefox() && this.getFirefoxVersion() < 65) ||
      (this.isChrome() && this.getChromeVersion() < 32)
    ) {
      return false;
    }
    url = token ? `${url}/tileImage.webp?token=${token}` : `${url}/tileImage.webp`;
    url = this.getRequestUrl(url, proxy);
    return FetchRequest.get(url, null, {
      withCredentials: this.isCredentail(url, proxy),
      withoutFormatSuffix: true
    })
      .then(function (response) {
        if (response.status !== 200) {
          throw response.status;
        }
        return response;
      })
      .then(() => {
        return true;
      })
      .catch(() => {
        return false;
      });
  }
  /**
   * @private
   * @function WebMap.prototype.isIE