remove spm

remove_spm.js

function modifyPage() {
  let forEach = Function.call.bind([].forEach);

  let removeSpm = (url, next) => {
    let search = url.search;
    if (!search) return;

    let query = parseQuery(search.slice(1));
    if (query.spm) {
      delete query.spm;
      let param = toParam(query);
      next(url.origin + url.pathname + (param ? "?" + param : "") + url.hash);
    }
  };

  let parseQuery = (param) => {
    return param
      .split("&")
      .map((pair) => pair.split("="))
      .reduce((o, p) => {
        o[p[0]] = decodeURIComponent(p[1]);
        return o;
      }, {});
  };

  let toParam = (object) => {
    return Object.keys(object)
      .map((key) => key + "=" + encodeURIComponent(object[key]))
      .join("&");
  };

  let removeLinkSpm = (link) => {
    removeSpm(link, (newUrl) => {
      link.href = newUrl;
    });
  };

  let removeLocationSpm = () => {
    removeSpm(location, (newUrl) => {
      history.replaceState(null, document.title, newUrl);
    });
  };

  let isLink = (node) => {
    return node && node.nodeName === "A";
  };

  let observer = new MutationObserver((mutations) => {
    mutations.forEach((mutation) => {
      let type = mutation.type;
      if (type === "attributes") {
        if (mutation.attributeName === "href" && isLink(mutation.target)) {
          removeLinkSpm(mutation.target);
        }
      } else if (type === "childList" || type === "subtree") {
        forEach(mutation.addedNodes, (node) => {
          if (isLink(node)) {
            removeLinkSpm(node);
          }
        });
      }
    });
  });

  observer.observe(document.body, {
    attributes: true,
    childList: true,
    subtree: true,
  });
  forEach(document.links, removeLinkSpm);
  removeLocationSpm();
}
modifyPage()