old_contents: const crawler = require("../dist");
  const spider = crawler("http://blog.npmjs.org/");
  
  spider.when("/post/[digit:id]/[all:slug]").then(({ req, res, uri }) => {
    const id = req.param("id");
    const slug = req.param("slug").split("?")[0];
  
    console.log(`[Info] Saving post with id: ${id} (${slug})`);
  });
  
  spider.on("start", () => {
    console.log("Start event");
  });
  
  spider.on("end", () => {
    console.log("End event");
  });
  
  spider.on("error", error => {
    console.log(`[Error] ${error}`);
  });
  
  spider.on("request", url => {
    console.log(`[Success] ${url}`);
  });
  
  spider.start();
  
new_contents: const crawler = require("../dist");
  const spider = crawler("http://blog.npmjs.org/");
  
  spider.when("/post/[digit:id]/[all:slug]", ({ req, res, uri }) => {
    const id = req.param("id");
    const slug = req.param("slug").split("?")[0];
  
    console.log(`[Info] Saving post with id: ${id} (${slug})`);
  });
  
  spider.on("start", () => {
    console.log("Start event");
  });
  
  spider.on("end", () => {
    console.log("End event");
  });
  
  spider.on("error", error => {
    console.log(`[Error] ${error}`);
  });
  
  spider.on("request", url => {
    console.log(`[Success] ${url}`);
  });
  
  spider.start();
  
subject: Update when usage example