CRA Workbox change

changeServiceWorker.js

const fs = require("fs");

function template (preCacheFile, blackList) {
    return `/**
    * Welcome to your Workbox-powered service worker!
    *
    * You'll need to register this file in your web app and you should
    * disable HTTP caching for this file too.
    * See https://goo.gl/nhQhGp
    *
    * The code below was initially generated by WorkBox but because
    * CRA doesn't allow blacklist customization "yet", run the node
    * command "bin/changeServiceWorker.js" after each build.
    */

   importScripts("https://storage.googleapis.com/workbox-cdn/releases/4.3.1/workbox-sw.js");

   importScripts(
     "/${preCacheFile}"
   );

   self.addEventListener('message', (event) => {
     if (event.data && event.data.type === 'SKIP_WAITING') {
       self.skipWaiting();
     }
   });

   workbox.core.clientsClaim();

   /**
    * The workboxSW.precacheAndRoute() method efficiently caches and responds to
    * requests for URLs in the manifest.
    * See https://goo.gl/S9QRab
    */
   self.__precacheManifest = [].concat(self.__precacheManifest || []);
   workbox.precaching.precacheAndRoute(self.__precacheManifest, {});
   // teste
   workbox.routing.registerNavigationRoute(workbox.precaching.getCacheKeyForURL("/index.html"), {

     blacklist: [/^\\/_/, /\\/[^\\/?]+\\.[^\\/]+$/${blackList ? "," + blackList : ""}],
   });
   `;
}

const blackList = `/api/`;
const buildDir = "./build";
const dir = fs.readdirSync(buildDir);
const swFile = dir.filter(function (elm) {
    return elm.match(/precache-manifest/gi);
})[0];

if (!swFile) {
    throw new Error("Not found file precache-manifest");
}

fs.writeFileSync(buildDir + "/service-worker.js", template(swFile, blackList));

add in your package.json